New Anesthetic Technique for Dacryocystorhinostomy: 218 Cases with Local-Anesthesia Ultrasonographic Guided and Blunt Cannula

Introduction: Epiphora is a common ophthalmologic complaint and referrals to oculoplastics and, in the presence of lower complete lacrimonasal duct obstruction, may lead to mild to severe complications, thus requiring surgery to create a new drainage path. The external dacryocystorhinostomy with silicon intubation is the surgical technique with better long-term outcomes and performed in the institutions where this study was conducted. Can be performed under either general or loco-regional anesthesia, or a combination of both. Methods: This article presents a revision of 218 consecutive cases from December 2016 to June 2021 in two specialized centers with the same stan-dardized surgical and anesthetic technique. Results: 242 surgical prontuaries were selected, with 218 filling the inclusion criteria. 13% of the patients required additional anesthetic infusion before the beginning of the surgery; 2.7% of the patients required field anesthetic infusion during the surgery and 6.4% required supplementary sedation, thus meaning a positive outcome, as the number of patients with intraoperative complaints was low, and the overall comfort was high. During the follow up, no patient required pain medication after 24 hours. Discussion: This study points towards the feasibility of the described technique in an outpatient fashion, with low, mild and tolerable side effects associated.


Introduction
Epiphora, or excessive lacrimonasal drainage is one of the most common ophthalmologic symptoms that leads to referrals to oculoplastics clinic for evaluation [1]. When caused by lower complete lacrimonasal duct obstruction, may be the initial presentation of a set of consequential events that can lead to dacryocystitis, abscess, fistulas, or, in extreme cases, meningoencefalitis [2] [3]. The origin of the obstruction may be congenital or acquired and, in order to be corrected, the most successful method is surgically made [4] [5]. Amongst several techniques, the external dacryocystorhinostomy (ED) with silicon intubation is still the one with the best outcomes and majority of studies so far [6] [7]. This surgery can be performed under general anesthesia, loco-regional or with a combination of both techniques. The ideal technique should achieve minimum bleeding rate, hospitalization time and require minimum post-operative analgesic compsumation [8] [9]. Loco-regional anesthesia is well stablished in adult population and is associated with less bleeding rate, hospitalization time and post-operative analgesic compsumation [8]. However, there is no effective padronized technique. After bibliographic consultation, it was proposed that the nerve territories that should be blocked to ensure adequate anesthesia would be nasocilliary, supra-trochlear, infra-trochlear, supra-orbitary and infra-orbitary [9] [10] [11] [12]. Each blockage territory is described individually for special situations, and also its ultrasound guidance, however, until june 2021 there were no studies combining these techniques for ED. In order to avoid minor hemorrhagic complications, it was proposed utilization of a sterile blunt cannula 25 G × 38 mm. Therefore, the padronized blockage was ultrasound guided of nasocilliary, supra-trochlear, infra-trochlear, supra-orbitary and infra-orbitary nerves, with the utilization of the above described blunt cannula. This prontuary revision accounts for 218 consecutive ED cases with the detailed description of this technique, adverse events and outcomes.

Methodology
This study was conducted in the archives section of Centro de Estudos e Pesquisas Oculistas Associados, Rio de Janeiro, RJ, Brazil, and Hospital do Olho Julio Candido de Brito, Duque de Caxias, RJ, Brazil. IRB from both institutions stated that this work adhered to the tenets of the Declaration of Helsinki. In July 2021, research was performed in the archives of both institutions participating in the presenting study and it was selected surgical prontuaries of 242 patients submit-ted to ED from December 2016 to June 2021. After verification of eligibility criteria, 24 were excluded. The remaining 218, were suited to evaluation and enrolled the study. It was utilized as inclusion criteria: complete prontuaries from patients above 18 years of age, submitted to ED under both same padronized surgical and anesthesia technique, where it could be retrieved the following data: surgery date, gender and age, initial anesthetic volume bolus (IAV), final anesthetic volume (FAV), initial sedation (IS), supplementary sedation required (SS) and analgesic consumption in the same day (AC1), 24 h after (AC2), 07 days after (AC3) and 30 days after (AC4), time (minutes) to hospitalar discharge and possible adverse events (tables 01 and 02). As exclusion criteria it was utilized: patients under 18 years of age and incomplete data. Padronized anesthesia technique in figs. 01 and 02. Before engaging the surgery all submitted patients were asked to sign a consent form stating fully awareness of both anesthetic and surgical process, with possible side effects and outcomes, along with authorization for publishing the results, with the due protection of their identities. Padronized anesthetic technique as follows: All patients in supine position. It was utilized sterile 25 G × 38 mm blunt cannula and Mobissom ® M4 wireless ultrasound 10 -14 MHz, set to depth at 2 -5 cm and a solution of Levobupivacaine 0.75% with hialuronidasis at 15 IU/mL. All patients had a 2% lidocaine and 1:200.000 adrenaline soaked gauze positioned in the middle nasal meatus.

Technique
Nasociliary nerve: cannula insertion must be above or bellow the caruncula, but not through, to avoid damage to its structure, and must be inserted with all range; At this site, 0.5 to 1.0 mL can be infused. Supratrochlear and infratrochlear nerves: after localization of the supero-medial orbitary angle, a small skin incision can be made with an insulin needle, and, thereafter, the cannula can be inserted towards the lacrimonasal crest, located profound to the medial cantal tendon; USG probe positioning is towards the medial cantal tendon; USG image, from anterior to posterior, shows skin, subcutaneous tissue, the medial cantal tendon and the caruncula, and periosteum adjacent to the tendon. The tip of the cannula must be located between the tendon and the periosteum. Anesthetic infusion must cause a tissue movement towards both superior and inferior directions from the structures around the medial cantal tendon. At this site, 2.5 to 3.5 mL of anesthetic solution can be infused Hospitalar discharge happened when the patients were fully alert, hemodynamically stable with post-anesthetic scale score of 09 or above.

Results
From the initially 242 surgical prontuaries in both institutions, 218 made it to the eligibility criteria. As exposed in Table 1, the majority of patients belonged to the feminine gender, with the average age of 62 years. Every patient received    an initial total anesthetic solution bolus of 7 mL and, immediately after the blockage, patients were accessed about loss of thermal sensibility in the corresponding dermatome. It was considered partial or complete anesthetic fail when thermal sensibility persisted in one given region. In that cases, additional anesthetic bolus (50% of anterior dose) were injected in the same territory, with the same technique, and the patient was evaluated again. When all the territories presented with loss of thermal sensibility, the surgery was cleared to begin. 29 (13%) patients required supplementary anesthetic volume infusion prior to clearance for surgery, but 04 (1.8%) presented with the complaint of pain or discomfort during nasolacrimal duct scarification and 2 (0.9%), during posterior wall of the lacrimal sac resection, solved with surgical field anesthetic infiltration. There was no necessity for RASS bellow 0. Supplementary analgesic or sedatives were necessary in 14 (6.4%) patients, half of them during osteotomy, when the main complaint was "awareness of the breaking of the bone", solved with propofol bolus infusion. 11 patients (5.0%) referred pain or discomfort during the bicanalicular silicone intubation, considered to be due to mispositioning of the intranasal gauze, solved by sufentanyl bolus. Every surgery was performed in a outpatient fashion and the average time needed to hospitalar discharge since the end of the procedure was 35 min. 23 patients referred mild PONV, responding to bromopride, 10 mg, single dose treatment. The outcome was positive, as postoperative analgesic consumption, intra-operative supplementary sedatives, analgesics or anesthetics and the number and quality of side effects were considered low, with a consequential high main overall satisfaction. During the follow up, 03 of the 212 patients required single dose analgesic for post operative nasal mucosa pain control in the immediate postoperative period, with 01 persisting in the first 24 hours, and no patient referred analgesic consumption in the 7 th and in the 30 th post operative day (Table 1 and Table 2).

Discussion
Loco-regional anesthesia is a viable technique for ED, safe to be utilized in a outpatient fashion, and promotes adequate pain control both intra and postoperative, although not free of adverse events [13]- [26]. The utilization of blunt cannula along with ultrasound guidance was associated with low anesthetic volumes and few adverse events related to this technique. In 1991, Dresner and colleagues suggested that ED could be performed safely in an outpatient Fashion [14]. Ferda Ciftci and colleagues, compared, in 2005, the effectiveness, complications and patient acceptance of local anesthesia with general anesthesia in young patients for ED [8]. In an 8-year period, 480 procedures were performed, being 298 with local anesthesia (LA), and the researchers concluded that there was better pain and bleeding control in this group, with also higher PONV rates in the general anesthesia (GA) group. All patients had hospital admission, one disadvantage, when compared to ours, performed essentially in an outpatient fashion. Although the nerve territories utilized to perform the blocks were different, their outcomes were similar to this study, but with a homogenic population, instead of a heterogenic one. McNab and colleagues, in 2002, had stablished the effectiveness of LA for ED, with similar findings, although, with the combination of sedation for comfort improvement. In our findings, the rate of supplementary LA infiltration was due to abscess, which can rise the local anesthetic requirements, besides loss of thermal sensation in the corresponding dermatome before clearance to surgery [10]. Supplementary sedation was also necessary in our study for anxiety due to awareness of the surgical step. As Ciftci concluded, adequate nerve block, with enough volume, could ensure high quality procedure, with an aware, satisfied patient. Although, the presence of an anxious patient and abscess brings the necessity to individualize patients care, these conclusions were also made in the study from Tawfik, in 2013, where it was necessary heavy sedation in 08 uncooperative patients, and supplementary LA in 04 patients for intolerable pain. Chaume, in 2010, stablished four nerve territories, in a study with 34 patients, with 88.4% of the patients declaring were ready to choose the same anesthetic protocol if new surgery was needed. The nerve territories utilized were almost the same as in this study, and the researchers discussed also that there are few studies focused in discuss ED under local anesthesia and sedation [11].
Sagiv and colleagues, in 2015 compared GA with LA, but this study also included an endoscopic approach, with similar surgical success rate between them, but with a higher success rate within the GA group [19].
Regarding the individual blockage procedure of each nerve territory, the utilization of a blunt cannula was considered easy and safe by the investigators with no adverse events associated. USG promoted better visualization of anatomical landmarks and the deposition of anesthetic volume, providing adequate anesthesia, with average anesthetic volume similar to the study from Ciftci, but lower than the others.
The surgical steps when patients referred pain or discomfort, were considered mild, tolerable and treatable by the team and the patients. Nasal mucosal discomfort accounted for 100% of patients' analgesic consumption in the postoperative period. Analgesic consumption was considered low, as there was no patient referred consuming more than the one dose only prescribed as "if necessary".

Limitations of the Study
As a retrospective descriptive case series, with only one exposure factor, no comparison was performed, consequentially, it was not possible to statistically determine the influence of the intervention in the outcome.

Conclusion
Although this research is a case series, with inherent limitations, such as low generalization, and biases associated to this model, it enlightens hypothesis formu-lations. This manuscript was important to the better knowledge of the anatomy of the face and the adjustment for reproducibility of the anesthetic technique. It is still necessary bigger studies in order to allow better understanding of the process, and thus even more efficient approach.