Biosensors: An Upcoming Wave of Innovation.

SUMMARY: A biosensor uses a biological molecule to measure a chemical reaction. Wearable biosensors that attach to the body externally, including tooth enamel biosensors, contact lens biosensors, sweat biosensors, and skin tattoo biosensors, are in development. Nanoparticle-based biosensors are being developed to allow for the early detection of cancerous biomarkers. Applications relevant to plastic surgery include the development of biosensors that can detect metastatic breast cancer cells, bioimpedance spectroscopy, and intraoperative point-of-care diagnostics.

Artificial Intelligence: Singularity Approaches.

SUMMARY: Artificial intelligence (AI) has been a disruptive technology within health care, from the development of simple care algorithms to complex deep-learning models. AI has the potential to reduce the burden of administrative tasks, advance clinical decision-making, and improve patient outcomes. Unlocking the full potential of AI requires the analysis of vast quantities of clinical information. Although AI holds tremendous promise, widespread adoption within plastic surgery remains limited. Understanding the basics is essential for plastic surgeons to evaluate the potential uses of AI. This review provides an introduction of AI, including the history of AI, key concepts, applications of AI in plastic surgery, and future implications.

Screening for lipid nanoparticles that modulate the immune activity of helper T cells towards enhanced antitumour activity.

Lipid nanoparticles (LNPs) can be designed to potentiate cancer immunotherapy by promoting their uptake by antigen-presenting cells, stimulating the maturation of these cells and modulating the activity of adjuvants. Here we report an LNP-screening method for the optimization of the type of helper lipid and of lipid-component ratios to enhance the delivery of tumour-antigen-encoding mRNA to dendritic cells and their immune-activation profile towards enhanced antitumour activity. The method involves screening for LNPs that enhance the maturation of bone-marrow-derived dendritic cells and antigen presentation in vitro, followed by assessing immune activation and tumour-growth suppression in a mouse model of melanoma after subcutaneous or intramuscular delivery of the LNPs. We found that the most potent antitumour activity, especially when combined with immune checkpoint inhibitors, resulted from a coordinated attack by T cells and NK cells, triggered by LNPs that elicited strong immune activity in both type-1 and type-2 T helper cells. Our findings highlight the importance of optimizing the LNP composition of mRNA-based cancer vaccines to tailor antigen-specific immune-activation profiles.

Vascularized Denervated Muscle Targets for Headache Surgery-Presentation and Surgical Management.

Patients with substantial trauma to their occipital nerves and those with recurrent or persistent chronic headaches after occipital nerve decompression surgery require transection of their greater occipital and/or lesser occipital nerves to control debilitating pain. Current techniques, such as burying the transected nerve stump in nearby muscle, do not prevent neuroma formation, and more advanced techniques, such as targeted muscle reinnervation and regenerative peripheral nerve interface, have demonstrated only short-term anecdotal success in the context of headache surgery. Vascularized denervated muscle targets (VDMTs) are a novel technique to address the proximal nerve stump after nerve transection that has shown promise to improve chronic nerve pain and prevent neuroma formation. However, VDMTs have not been described in the context of headache surgery. Here authors describe the etiology, workup, and surgical management of 2 patients with recurrent occipital neuralgia who developed vexing neuromas after previous surgery and were successfully treated with VDMTs, remaining pain-free at 3-year follow-up.

Robotics in Plastic Surgery: It's Here.

SUMMARY: Although robotic surgery has been routinely established in other surgical disciplines, robotic technologies have been less readily adopted in plastic surgery. Despite a strong demand for innovation and cutting-edge technology in plastic surgery, most reconstructive procedures, including microsurgery, have continued to necessitate an open approach. Recent advances in robotics and artificial intelligence, however, are gaining momentum and have shown significant promise to improve patient care in plastic surgery. These next-generation surgical robots have the potential to enable surgeons to perform complex procedures with greater precision, flexibility, and control than previously possible with conventional techniques. Successful integration of robotic technologies into clinical practice in plastic surgery requires achieving key milestones, including implementing appropriate surgical education and garnering patient trust.

Cybersecurity and Technical Patient Privacy Protection.

Plastic surgery offices are subject to a wide variety of cybersecurity threats, including ransomware attacks that encrypt the plastic surgeon's information and make it unusable, as well as data theft and disclosure attacks that threaten to disclose confidential patient information. Cloud-based office systems increase the attack surface and do not mitigate the effects of breaches that can result in theft of credentials. Although employee education is often recommended to avoid the threats, a single error by a single employee has often led to security breaches, and it is not reasonable to expect that no employee will ever make an error. A recognition of the two most common vectors of these breaches, compromised email attachments and surfing to compromised websites, allows the use of technical networking tools to both prevent email attachments from being received and to prevent employee use of unsanctioned and potentially compromised websites. Further, once compromised code is allowed to run within the office network, that code must necessarily make outbound connections to exploit the breach. Preventing that outbound traffic can mitigate the effects of a breach. However, most small office network consultants design firewalls to only limit incoming network traffic and fail to implement technical measures to stop the unauthorized outbound traffic that is necessary for most network attacks. Detailed techniques are provided which can be used to direct IT consultants to properly limit outbound network traffic as well as incoming email attachments, with more information at https://officenetworksecurity.com.

Treatment of Persistent Post-traumatic Diplopia - An Algorithmic Approach to Patient Stratification and Operative Management.

Study Design: Retrospective chart review of revisional orbital surgery outcomes in patients with diplopia from prior operative treatment of orbital trauma. Objective: Our study seeks to review our experience with management of persistent post-traumatic diplopia in patients with previous orbital reconstruction and present a novel patient stratification algorithm predictive of improved outcomes. Methods: A retrospective chart review was performed on adult patients at Wilmer Eye Institute at Johns Hopkins Hospital and at the University of Maryland Medical Center who underwent revisional orbital surgery for correction of diplopia for the years 2005-2020. Restrictive strabismus was determined by Lancaster red-green testing coupled with computed tomography and/or forced duction. Globe position was assessed by computed tomography. Seventeen patients requiring operative intervention according to study criteria were identified. Results: Globe malposition affected fourteen patients and restrictive strabismus affected eleven patients. In this select group, improvement in diplopia occurred in 85.7% of cases with globe malposition and in 90.1% of cases with restrictive strabismus. One patient underwent additional strabismus surgery subsequent to orbital repair. Conclusions: Post-traumatic diplopia in patients with prior orbital reconstruction can be successfully managed in appropriate patients with a high degree of success. Indications for surgical management include (1) globe malposition and (2) restrictive strabismus. High resolution computer tomography and Lancaster red-green testing discriminate these from other causes that are unlikely to benefit from orbital surgery.

Breast Reconstruction Trends in the Setting of Postmastectomy Radiation Therapy: Analysis of Practices among Plastic Surgeons in the United States.

Radiation is an integral part of breast cancer therapy. The ideal type and timing of breast reconstruction with relation to radiation delivery are not well established. The study aimed to identify reconstructive practices among American plastic surgeons in the setting of pre- and postmastectomy radiation. Methods: A cross-sectional survey of members of the American Society of Plastic Surgery was performed. Practice/demographic information and breast reconstruction protocols were queried. Univariate descriptive statistics were calculated, and outcomes were compared across cohorts with χ2 and Fischer exact tests. Results: Overall, 477 plastic surgeons averaging 16.3 years in practice were surveyed. With respect to types of reconstruction, all options were well represented, although nearly 60% preferred autologous reconstruction with prior radiation and 55% preferred tissue expansion followed by implant/autologous reconstruction in the setting of unknown postoperative radiation. There was little consensus on the optimal timing of reconstruction in the setting of possible postoperative radiation. Most respondents wait 4-6 or 7-12 months between the end of radiation and stage 2 implant-based or autologous reconstruction. Common concerns regarding the effect of radiation on reconstructive outcomes included mastectomy flap necrosis, wound dehiscence, capsular contracture, tissue fibrosis, and donor vessel complications. Conclusions: Despite considerable research, there is little consensus on the ideal type and timing of reconstruction in the setting of pre- and postoperative radiation. Understanding how the current body of knowledge is translated into clinical practice by different populations of surgeons allows us to forge a path forward toward more robust, evidence-based guidelines for patient care.

Perforator Characteristics and Impact on Postoperative Outcomes in DIEP Flap Breast Reconstruction: A Systematic Review and Meta-Analysis.

BACKGROUND: High-quality evidence on perforator selection in deep inferior epigastric perforator (DIEP) flap harvesting is lacking, making preoperative planning and choice of perforators "surgeon-specific." This lack of consensus is a subject of continuous debate among microsurgeons. We aimed to systematically review perforator characteristics and their impact on DIEP flap breast reconstruction outcomes. METHODS: We conducted a systematic review and meta-analysis across six databases: ClinicalTrials.gov, Cochrane Library, Medline, Ovid Embase, PubMed, and Web of Science for all studies on DIEP flap breast reconstruction focused on perforator characteristics-caliber, number, and location. The primary goal was to analyze the impact of perforator characteristics on partial and/or total flap failure and fat necrosis. Data was analyzed using RevMan V5.3. RESULTS: Initial search gave us 2,768 articles of which 17 were included in our review. Pooled analysis did not show any statistically significant correlations between partial and/or total flap failure and perforator number, or perforator location. Sensitivity analysis accounting for heterogeneity across studies showed that, the risk for fat necrosis was significantly higher if single perforators (relative risk [RR] = 2.0, 95% confidence interval [CI] = 1.5-2.6, I 2 = 39%) and medial row perforators (RR = 2.7, 95% CI = 1.8-3.9, I 2 = 0%) were used. CONCLUSION: Our findings suggest that a single dominant perforator and medial row perforators may be associated with higher risk of fat necrosis after DIEP flap breast reconstruction. Adopting a standardized perforator selection algorithm may facilitate operative decision making, shorten the learning curve for novice surgeons, and optimize postoperative outcomes by minimizing the burden of major complications. This in turn would help improve patient satisfaction and quality of life.

A 10-Year Review of Surgical Outcomes at the Johns Hopkins and University of Maryland Resident Aesthetic Clinic.

Background: In 2014, the Plastic Surgery Residency Review Committee of the Accreditation Council for Graduate Medical Education (ACGME) increased minimum aesthetic surgery requirements. Consequently, the resident aesthetic clinic (RAC) has become an ever more important modality for training plastic surgery residents. Objectives: To analyze demographics and long-term surgical outcomes of aesthetic procedures performed at the Johns Hopkins and University of Maryland (JH/UM) RAC. A secondary objective was to evaluate the JH/UM RAC outcomes against those of peer RACs as well as board-certified plastic surgeons. Methods: We performed a retrospective chart review of all patients who underwent aesthetic procedures at the JH/UM RAC between 2011 and 2020. Clinical characteristics, minor complication rates, major complication rates, and revision rates from the JH/UM RAC were compared against 2 peer RACs. We compared the incidence of major complications between the JH/UM RAC and a cohort of patients from the CosmetAssure (Birmingham, AL) database. Pearson's chi-square test was used to compare complication rates between patient populations, with a significance set at 0.05. Results: Four hundred ninety-five procedures were performed on 285 patients. The major complications rate was 1.0% (n = 5). Peer RACs had total major complication rates of 0.2% and 1.7% (P = .07 and P = .47, respectively). CosmetAssure patients matched to JH/UM RAC patients were found to have comparable total major complications rates of 1.8% vs 0.6% (P = .06), respectively. At JH/UM, the minor complication rate was 13.9%, while the revision rate was 5.9%. Conclusions: The JH/UM RAC provides residents the education and training necessary to produce surgical outcomes comparable to peer RACs as well as board-certified plastic surgeons.

CODA: quantitative 3D reconstruction of large tissues at cellular resolution.

A central challenge in biology is obtaining high-content, high-resolution information while analyzing tissue samples at volumes relevant to disease progression. We address this here with CODA, a method to reconstruct exceptionally large (up to multicentimeter cubed) tissues at subcellular resolution using serially sectioned hematoxylin and eosin-stained tissue sections. Here we demonstrate CODA's ability to reconstruct three-dimensional (3D) distinct microanatomical structures in pancreas, skin, lung and liver tissues. CODA allows creation of readily quantifiable tissue volumes amenable to biological research. As a testbed, we assess the microanatomy of the human pancreas during tumorigenesis within the branching pancreatic ductal system, labeling ten distinct structures to examine heterogeneity and structural transformation during neoplastic progression. We show that pancreatic precancerous lesions develop into distinct 3D morphological phenotypes and that pancreatic cancer tends to spread far from the bulk tumor along collagen fibers that are highly aligned to the 3D curves of ductal, lobular, vascular and neural structures. Thus, CODA establishes a means to transform broadly the structural study of human diseases through exploration of exhaustively labeled 3D microarchitecture.

Biostimulatory Micro-Fragmented Nanofiber-Hydrogel Composite Improves Mesenchymal Stem Cell Delivery and Soft Tissue Remodeling.

Functional microgels are preferred stem cell carriers due to the ease of delivery through minimally invasive injection and seamless integration with the surrounding host tissue. A biostimulatory nanofiber-hydrogel composite (NHC) has been previously developed through covalently crosslinking a hyaluronic acid hydrogel network with surface-functionalized poly (ε-caprolactone) nanofiber fragments. The NHC mimics the microarchitecture of native soft tissue matrix, showing enhanced cell infiltration, immunomodulation, and proangiogenic properties. Here, injectability of the pre-formed NHC is improved by mechanical fragmentation, making it into micro-fragmented NHC (mfNHC) in a granular gel form as a stem cell carrier to deliver mesenchymal stem cells (MSCs) for soft tissue remodeling. The mfNHC shows a similar storage modulus but a significantly reduced injection force, as compared with the corresponding bulk NHC. When injected subcutaneously in a rat model, mfNHC-MSC constructs initiate an elevated level of host macrophage infiltration, more pro-regenerative polarization, and subsequently, improved angiogenesis and adipogenesis response when compared to mfNHC alone. A similar trend of host cell infiltration and pro-angiogenic response is detected in a swine model with a larger volume injection. These results suggest a strong potential for use of the mfNHC as an injectable carrier for cell delivery and soft tissue remodeling.

The Effects of the Combination of Mesenchymal Stromal Cells and Nanofiber-Hydrogel Composite on Repair of the Contused Spinal Cord.

A bone marrow-derived mesenchymal stromal cell (MSC) transplant and a bioengineered nanofiber-hydrogel composite (NHC) have been shown to stimulate nervous tissue repair in the contused spinal cord in rodent models. Here, these two modalities were combined to assess their repair effects in the contused spinal cord in adult rats. Cohorts of contused rats were treated with MSC in NHC (MSC-NHC), MSC in phosphate-buffered saline (MSC-PBS), NHC, or PBS injected into the contusion site at 3 days post-injury. One week after injury, there were significantly fewer CD68+ cells in the contusion with MSC-NHC and NHC, but not MSC-PBS. The reduction in CD86+ cells in the injury site with MSC-NHC was mainly attributed to NHC. One and eight weeks after injury, we found a greater CD206+/CD86+ cell ratio with MSC-NHC or NHC, but not MSC-PBS, indicating a shift from a pro-inflammatory towards an anti-inflammatory milieu in the injury site. Eight weeks after injury, the injury size was significantly reduced with MSC-NHC, NHC, and MSC-PBS. At this time, astrocyte, and axon presence in the injury site was greater with MSC-NHC compared with MSC-PBS. We did not find a significant effect of NHC on MSC transplant survival, and hind limb function was similar across all groups. However, we did find fewer macrophages at 1 week post-injury, more macrophages polarized towards a pro-regenerative phenotype at 1 and 8 weeks after injury, and reduced injury volume, more astrocytes, and more axons at 8 weeks after injury in rats with MSC-NHC and NHC alone compared with MSC-PBS; these findings were especially significant between rats with MSC-NHC and MSC-PBS. The data support further study in the use of an NHC-MSC combination transplant in the contused spinal cord.

A Markov Analysis of Surgical versus Medical Management of Chronic Migraines.

BACKGROUND: Refractory chronic migraine is a common and debilitating neurologic condition, affecting over 8 million people in the United States. It is associated with billions of dollars in lost productivity annually. Novel medical (anti-calcitonin gene-related peptide antibodies) and surgical treatment modalities have emerged for chronic migraine in recent years. The current study investigated the cost-utility of surgical versus medical management of refractory chronic migraine. METHODS: A Markov cohort analysis using hybrid Monte Carlo patient simulation was performed to compare surgical decompression versus erenumab for the treatment of refractory chronic migraine in adults. Both societal and payer perspectives were considered. Primary model outcomes included incremental cost-effectiveness ratio, or cost per quality-adjusted life-year gained. RESULTS: Over a 5-year period, migraine surgery was associated with an increase of 0.2 quality-adjusted life-year per patient when compared to erenumab. In terms of costs, the results demonstrated a $19,337 decrease in direct medical costs and a $491 decrease in indirect costs (productivity lost) for the surgery cohort compared to erenumab. Because surgery improved quality of life and decreased costs compared to erenumab, even when considering revision surgery needs, surgery was the overall dominant treatment in terms of cost-effectiveness. Sensitivity analyses demonstrated that surgery was cost-effective compared to erenumab when patients required therapy for at least 1 year. CONCLUSIONS: Surgical deactivation of migraine trigger sites may pose a cost-effective approach to treating refractory chronic migraine in adults. This is especially the case when patients are anticipated to require therapy for more than 1 year.

Enrichment of Nanofiber Hydrogel Composite with Fractionated Fat Promotes Regenerative Macrophage Polarization and Vascularization for Soft-Tissue Engineering.

BACKGROUND: Fractionated fat has been shown to promote dermal regeneration; however, the use of fat grafting for reconstruction of soft-tissue defects is limited because of volume loss over time. The authors have developed a novel approach for engineering of vascularized soft tissue using an injectable nanofiber hydrogel composite enriched with fractionated fat. METHODS: Fractionated fat was generated by emulsification of groin fat pads from rats and mixed in a 3:1 ratio with nanofiber hydrogel composite (nanofiber hydrogel composite with fractionated fat). Nanofiber hydrogel composite with fractionated fat or nanofiber hydrogel composite alone was placed into isolation chambers together with arteriovenous loops, which were subcutaneously implanted into the groin of rats (n = 8 per group). After 21 days, animals were euthanized and systemically perfused with ink, and tissue was explanted for histologic analysis. Immunofluorescent staining and confocal laser scanning microscopy were used to quantify CD34+ progenitor cell and macrophage subpopulations. RESULTS: Nanofiber hydrogel composite with fractionated fat tissue maintained its shape without shrinking and showed a significantly stronger functional vascularization compared to composite alone after 21 days of implantation (mean vessel count, 833.5 ± 206.1 versus 296.5 ± 114.1; p = 0.04). Tissue heterogeneity and cell count were greater in composite with fractionated fat (mean cell count, 49,707 ± 18,491 versus 9263 ± 3790; p = 0.005), with a significantly higher number of progenitor cells and regenerative CD163+ macrophages compared to composite alone. CONCLUSIONS: Fractionated fat-enriched nanofiber hydrogel composite transforms into highly vascularized soft tissue over 21 days without signs of shrinking and promotes macrophage polarization toward regenerative phenotypes. Enrichment of injectable nanofiber hydrogel composite with fractionated fat represents a promising approach for durable reconstruction of soft-tissue defects. CLINICAL RELEVANCE STATEMENT: The authors' approach for tissue engineering may ultimately lay the groundwork for clinically relevant applications with the goal of generating large volumes of vascularized soft tissue for defect reconstruction without donor site morbidity.

Neuroma of The Supraorbital Nerve Following Forehead Flap Reconstruction - Presentation and Surgical Management.

ABSTRACT: Localized pain or headache from neuroma formation is a rare and challenging complication of forehead flap surgery. Here the authors present a patient who developed local pain and dysesthesia following iatrogenic injury to the left supraorbital nerve during forehead flap elevation. Following a diagnostic nerve block in clinic, surgical excision of the neuroma was performed through an upper blepharoplasty approach. The patient had immediate postoperative pain relief and remains pain free at fifteen-month follow-up. The authors describe etiology, workup, and surgical management of sensory nerve injury during forehead flap reconstruction.

Management of Teeth in the Line of Mandibular Angle Fractures Treated with Open Reduction and Internal Fixation: A Systematic Review and Meta-Analysis.

BACKGROUND: Mandibular angle fractures are common and frequently involve a tooth in the fracture line. Despite trends toward more conservative indications for tooth extraction during open repair, the literature remains heterogeneous. This review aims to ascertain the effect of tooth extraction/retention on patient outcomes following mandible open reduction and internal fixation and to evaluate the evidence surrounding indications for extraction. METHODS: PubMed, EMBASE, the Cochrane Library, Elsevier text mining tool database, and clinicaltrials.gov were queried through March of 2018 for English language publication on adults with traumatic mandibular fractures. The review protocol was not registered online. Quality of evidence was assigned using the Grading of Recommendations Assessment, Development and Evaluation methodology. Meta-analyses were performed when definitions of outcomes were deemed similar. RESULTS: Overall, 26 of 1212 identified studies met inclusion criteria. Indications for tooth extraction and rates of extraction varied considerably across studies. The quality of evidence was low or very low for all outcomes. Tooth retention was associated with lower overall complications (OR, 0.54; 95 percent CI, 0.37 to 0.79), major complications requiring readmission or reoperation (OR, 0.47; 95 percent CI, 0.24 to 0.92), and malocclusion (OR, 0.56; 95 percent CI, 0.32 to 0.97); there was no difference in wound issues or nonunion. Removal of asymptomatic teeth was associated with inferior alveolar nerve injury (39.4 percent versus 16.1 percent). CONCLUSIONS: The literature is limited by retrospective study deign and poor follow-up; however, when indicated, tooth extraction is not associated with an increased risk of infection or nonunion. Removal of asymptomatic teeth was associated with a risk of inferior alveolar nerve injury. Additional high-quality studies are needed to evaluate potentially expanded indications for tooth extraction.

Nanofiber-hydrogel composite-mediated angiogenesis for soft tissue reconstruction.

Soft tissue losses from tumor removal, trauma, aging, and congenital malformation affect millions of people each year. Existing options for soft tissue restoration have several drawbacks: Surgical options such as the use of autologous tissue flaps lead to donor site defects, prosthetic implants are prone to foreign body response leading to fibrosis, and fat grafting and dermal fillers are limited to small-volume defects and only provide transient volume restoration. In addition, large-volume fat grafting and other tissue-engineering attempts are hampered by poor vascular ingrowth. Currently, there are no off-the-shelf materials that can fill the volume lost in soft tissue defects while promoting early angiogenesis. Here, we report a nanofiber-hydrogel composite that addresses these issues. By incorporating interfacial bonding between electrospun poly(ε-caprolactone) fibers and a hyaluronic acid hydrogel network, we generated a composite that mimics the microarchitecture and mechanical properties of soft tissue extracellular matrix. Upon subcutaneous injection in a rat model, this composite permitted infiltration of host macrophages and conditioned them into the pro-regenerative phenotype. By secreting pro-angiogenic cytokines and growth factors, these polarized macrophages enabled gradual remodeling and replacement of the composite with vascularized soft tissue. Such host cell infiltration and angiogenesis were also observed in a rabbit model for repairing a soft tissue defect filled with the composite. This injectable nanofiber-hydrogel composite augments native tissue regenerative responses, thus enabling durable soft tissue restoration outcomes.

Fibroblast Growth Factor Receptor 2 (FGFR2) Mutation Related Syndromic Craniosynostosis.

Craniosynostosis results from the premature fusion of cranial sutures, with an incidence of 1 in 2,100-2,500 live births. The majority of cases are non-syndromic and involve single suture fusion, whereas syndromic cases often involve complex multiple suture fusion. The fibroblast growth factor receptor 2 (FGFR2) gene is perhaps the most extensively studied gene that is mutated in various craniosynostotic syndromes including Crouzon, Apert, Pfeiffer, Antley-Bixler, Beare-Stevenson cutis gyrata, Jackson-Weiss, Bent Bone Dysplasia, and Seathre-Chotzen-like syndromes. The majority of these mutations are missense mutations that result in constitutive activation of the receptor and downstream molecular pathways. Treatment involves a multidisciplinary approach with ultimate surgical fixation of the cranial deformity to prevent further sequelae. Understanding the molecular mechanisms has allowed for the investigation of different therapeutic agents that can potentially be used to prevent the disorders. Further research efforts are need to better understand screening and effective methods of early intervention and prevention. Herein, the authors provide a comprehensive update on FGFR2-related syndromic craniosynostosis.

Injured Anterior Superior Alveolar Nerve Endoscopically Resected within Maxillary Sinus.

Posttraumatic facial pain is due to an injured nerve, most often a branch of the trigeminal nerve. While surgical approaches to injuries of the supraorbital, supratrochlear, infraorbital, and inferior alveolar nerves have been reported, an injury to the anterior superior alveolar nerve (ASAN) has not been reported. An algorithm is proposed for the diagnosis of injury to the ASAN versus the infraorbital nerve itself. A case is reported in which pain relief was achieved by dividing the ASAN within the maxillary sinus, leaving the proximal end exposed within the sinus at the level of the orbital floor.