Patient Comfort: Analgesia & Anesthesia

Malcolm G. Munro MD, FRCSC, FACOG

KEY POINTS

While many women, particularly those who require diagnostic hysteroscopy only, require no analgesia, many require uterine anesthesia be it using local, regional or general anesthetic techniques.
Anxiety contributes to the perception of pain, so when performing hysteroscopic procedures in an office or clinic environment, efforts should be made to reduce anxiety based on the appearance of the room, its temperature and the general mood which can be affected by noise or other interruptions and the comportment of the medical and support staff.
Women should be reassured that if the procedure causes undue pain, it will be terminated and plans made to complete it at a later time and possibly under different conditions such as with different anesthesia and possibly in an alternate location.
There is evidence that music reduces both anxiety and pain.
There is high quality evidence that, at least for diagnostic hysteroscopy, the vaginoscopic technique is feasible and comfortable for the vast majority of women.
Local anesthetic techniques, appropriately applied, can allow the performance of the entire spectrum of hysteroscopic surgical procedures. There is increasing evidence that the vagina and the entire uterus should be considered and approach that recognizes the unique and variable innervation of the uterus.
Regardless of the analgesia or anesthetic technique used women should be encouraged to have a support individual available to accompany them home following the procedure. This is mandatory should psychoactive or systemic anesthetic agents be used for the procedure.

INTRODUCTION

An increasing proportion of hysteroscopic procedures can be performed in the office or procedure room setting without the need for systemic anesthesia. This change is related to a number of factors including improved equipment design, the evolution in surgical technique, improved insight into the complexity of pelvic innervation and attention to the appropriate use of local anesthetic agents. It is important to know that the value of local anesthesia is controversial but there is increasing evidence that it has an important role in the migration of procedures from the institutional operating room setting to the office or clinic procedure room.

BACKGROUND CONSIDERATIONS

There exist a number of factors necessary to the success of hysteroscopic surgery in an office setting. First of all, the procedure environment must be clean and comfortable. Then, equipment and supplies must be well maintained, appropriate for the procedure, clean or sterile as required and redundancy adequate to compensate for malfunction or accidental contamination. The gynecologic surgeon must carefully select patients appropriate for the procedure being performed and exclude those with medical issues that would make local anesthesia an inappropriate choice. Since effective uterine anesthesia is important in at least many cases, it is essential that the surgeon understand the relatively complex innervation of the uterus including the variation in this anatomy amongst women. It is also important for the gynecologic surgeon to possess a working understanding of the pharmacodynamic principles of the local anesthetic agents used, and, in particular, the time required between application or injection and the achievement of maximal anesthesia.

For access to the cervical canal and endometrial cavity it is necessary to expose the cervix, a process that typically, but not always, requires the placement of a vaginal speculum. Positioning a vaginal speculum represents another potential source of discomfort or even pain during the performance of hysteroscopic procedures, a circumstance that may be especially true for women with levator spasm or those postmenopausal women with vaginal atrophy. The uterine related pain experienced by a patient undergoing hysteroscopy is likely related to several factors. The diameter of the cervical canal is generally larger in caliber in premenopausal women who have had vaginal deliveries than in those who are nulliparous or have had only abdominal deliveries. There may be differences in endometrial innervation as well including that of the functionalis layer that contains nerve fibers that appear to be increased in concentration in women with endometriosis (1, 2). This may explain the differences between the reaction to touching the endometrial surfaces for different women. These and other differences, yet to be defined, may have an impact on the perception of pain with cervical or intracavitary manipulation with instrumentation of similar dimensions.

Understanding these issues and having the discipline to await the appropriate amount of time to achieve the optimal anesthetic effect are critical to achieving the diagnostic and therapeutic goals while providing a comfortable experience for

LOCAL ANESTHETIC AGENTS

Mechanism of Action and Metabolism

The mechanism of action of local anesthetics is generally based on their ability to reversibly block and inactivate sodium channels in the cell membrane of sensory nerves thereby impeding the formation of an action potential and transmission of the sensation of pain to the higher neurons. These pharmaceutical agents are largely metabolized in the liver and have a half-life that typically ranges from 1.5 to 3 hours depending on the specific molecule and a number of other factors. While cocaine was the first local agent identified, most are derivatives of either an amino amide or amino ester class, the latter being modified versions of para-aminobenzoic acid (PABA) that are also associated with a greater incidence of allergic reaction. (Table 1)

Table 1. Categories of Local Anesthetics

Category	Generic Name	Trade Name
Amides	lidocaine, lignocaine	Xylocaine
	bupivacaine	Marcaine
	mepivacaine	Carbocaine
	prilocaine	Citnatest
	etidocaine	Duranest
Esters (Contain PABA)	procaine	Novicaine
	chloroprocaine	Nesacaine
	tetracaine	Pontocaine

Factors Affecting Potency and Onset and Duration of Action

The overall action and effect of a given local anesthetic agent is related to a number of factors including the time to onset of the anesthetic effect, the time to the maximum effect and the overall duration of action, characteristics that have a relationship to the features of the molecule itself. (Table 2)

There are a number of variables that impact the onset and duration of action of injectable local anesthetics, some of which are more important than others. The most obvious characteristic affecting the time of onset and maximal degree of anesthetic effect is the concentration of the anesthetic solution – local anesthetic concentrations are generally expressed as a percentage (e.g. lidocaine 0.5 to 2%, bupivicaine 0.25 to 0.5%). However, the simple concentration of the agent doesn't take into account the impact of the specific characteristics of the molecule or formulation on the anesthetic effect or even the potential adverse impact on patients to whom it is administered. For example, protein binding has a particular effect - procaine is bound about 6% to protein and therefore has a short duration of action while bupivicaine, which is 95% protein bound, has a relatively prolonged effect. The local pH and that of the anesthetic agent also is important. For example the PKa of the formulation has a significant impact on rapidity of action; weak bases (pH 7.6-7.8 such as lidocaine and mepivicaine) are associated with a more rapid onset of anesthetic effect while, more basic solutions (pH 8.1 - 8.9 procaine, tetracaine and bupivicaine) are much slower acting. Furthermore, when the pH of the injected agent is similar to that of the tissue, there is greater penetration of nonionized anesthetic particles into and through the lipid rich nerve cell membrane(3, 4, 5). The duration of action of a local anesthetic can be increased by the concomitant use of locally administered epinephrine, an approach that both decreases local systemic absorption and increases local pH. (Table 2)

Table 2. Commonly used local anesthetics, onset, duration, dose

For topically applied agents the onset of action, the depth of anesthesia and the duration of anesthetic action depend upon a variety of factors that include the concentration of the anesthetic agent, the time since application, the characteristics of the vehicle containing the agent and the nature and integrity of the epithelial surface being treated. An example of optimizing the vehicle is the use of a liposomal matrix that can deliver the agent more rapidly by facilitating absorption through the epithelium and neural membrane (3). Another consideration linked to topical application is that of systemic absorption of the local anesthetic agent, the degree of which is dependent upon the location of application and the nature, integrity and vascularity of the epithelial surface.

Adverse Events

While significant adverse reactions to local anesthetic agents are rare with appropriate use such events can occur. They are generally related to high plasma concentrations usually secondary to one or a combination of excessive dose, often due to inadvertent intravascular injection, or delayed clearance or impaired metabolism. The potential neurologic effects of overly high plasma levels include tremor, dizziness, blurred vision, perioral tingling and seizures – and, most importantly can respiratory depression and apnea. There are also cardiovascular side effects that are generally related to depression of myocardial activity that manifest in bradycardia and potential cardiovascular collapse - an adverse event more commonly described in association with bupivicaine. Another adverse reaction that is perhaps misperceived is IgE-mediated allergy, an event usually associated with the ester class of anesthetics and the immunogenicity of PABA. The amino amide-based anesthetics such as lidocaine, bupivicaine, and mepivacaine do not contain PABA, a feature that has contributed both to the popularity and the safety of these agents (Table 1).

The clinically significant adverse events associated with injectable local anesthetics are essentially eliminated by screening for allergy and by paying strict attention to both total dosage (in mg/kg) and injection technique being careful to avoid intravascular injection. The use of formulations that contain dilute epinephrine also reduce risk by containing the anesthetic agent locally while reducing systemic concentrations.

INNERVATION of the UTERUS

The innervation of the uterus is complex, and, to an extent, variable and entirely autonomic (6). The sympathetic component is derived from the inferior hypogastric plexus while the parasympathetic aspects arise from the pelvic splanchnic nerves that serve the cervix have their roots in S 2, 3 and 4. These roots can be considered to provide the primary innervation of the uterus via Frankenhauser’s (uterovaginal) plexus located near the cardinal ligament. (Figure 1)

Figure 1. Uterine Innervation (used with permission)

The afferent fibers travel from the corpus with the sympathetic nerves to the T 10-12 and L 1 roots. The hypogastric nerves on the right and left side link to the inferior hypogastric plexi that is located over the posterolateral pelvis, and then pass behind the common iliac arteries before they supply the uterus and upper two thirds of the vagina via the uterosacral and cardinal ligaments. The afferent fibers travel between the corpus with the sympathetic nerves to the T 11-12 and L 1 roots. The nerves extend through myometrium to the endometrial-myometrial interface where there exists a relatively well-defined plexus. Indeed the basal third of the endometrium is also innervated and neural fibers have been demonstrated in the superficial, functionalis. The third component of uterine innervation is the uterine fundus which is variably innervated by fibers from T10 and the ovarian plexus that reach the uterus through the infundibulopelvic ligament and then the cornea (Figure 1).

ANESTHETIC TARGETS & TECHNIQUES

The procedure to be performed and the variable sources of innervation should be considered when designing local anesthetic strategies.

Vaginal Anesthesia

There are relatively few data guiding the use of vaginal anesthesia. The first published study was a placebo-controlled RCT evaluating topical vaginal 10% lidocaine spray in women undergoing brachytherapy for cervical cancer that demonstrated a significant decrease in the amount of pain during placement of ovoids(7). However, a more recent randomized trial was designed to evaluate the impact of topical anesthesia on speculum placement in postmenopoausal women. The double blinded randomized trial compared placebo to a topical 2.5% xylocaine and 2.5% prilocaine combination administered minutes prior to the insertion of a speculum. The approach was demonstrated to significantly reduce perceived pain in all aspects of speculum manipulation - placement, opening and removal (8).

Cervical Anesthesia

Paracervical

The concept of the paracervical block is to obtain anesthesia by injecting a local anesthetic agent into the structures around cervix thereby capturing cervical innervation. Unfortunately, there are many paracervical techniques that differ substantially with respect to location(s) and depth of injection, the anesthetic agent and its concentration and the interval of time allowed between administration and commencement of the procedure. High quality randomized trials designed to evaluate paracervical local anesthesia for hysteroscopy or D&C have demonstrated a spectrum of results ranging from no measurable effect (9, 10) to a significant difference (11, 12, 13, 14) in measured pain scores. Consequently, it is not surprising that systematic review and metaanalysis of the available randomized trials led to the conclusion that paracervical anesthesia has questionable value (10). However, review of these trials suggests both variance in technique and design. In particular, many of the studies that showed no difference in pain outcome allowed relatively little time between injection and the commencement of the uterine procedure. This circumstance suggests that allowing for a longer time between paracervical injection and uterine manipulation is likely necessary to a measurable and optimal anesthetic effect.

Intracervical

Performance of an intracervical block requires direct injection of the local anesthetic into the cervical stroma using any of several techniques. As with paracervical block, there is wide variation in technique including the usual inconsistency in injection-procedure times using a spectrum of local anesthetic agents and dose. Nonetheless the technique has been described successful in relatively large series of resectoscopic endometrial ablation cases with relatively large-diameter instruments – up to 9 mm (5, 6). The only identified placebo controlled randomized trial demonstrated reduced pain in the lidocaine group during insertion of a hysteroscope but the pain of injection was as severe as that of the procedure itself (17).

Topical Cervical

Application of topical gels, creams, or spray solutions to either to the exocervix or in the cervical canal has been evaluated in the literature. One technique for accessing the cervical canal involves placing a tenaculum on the cervix, a technique that can cause substantial pain. A well-designed, placebo-controlled randomized trial has demonstrated reduced pain associated with attachment of a tenaculum (18). When we use a tenaculum, superficial intracervical injection of ½% lidocaine with 1/200,000 epinephrine is used – although this has not been evaluated in randomized trials.

Topical agents applied to the cervical canal have been evaluated and also met with mixed results in comparative trials. While a placebo controlled RCT of patients undergoing hysteroscopy showed no value to the use of 10% lidocaine solution (18) other RCTs demonstrated that 5% lidocaine gel (19) or EMLA (the combination of 2.5% lidocaine/2.5% prilocaine in a cream) or lidocaine spray were associated with a significant reduction in procedure pain (20).

Uterine Corpus Anesthesia

Injection

It is possible, at least theoretically, to provide a degree of anesthesia to the uterine corpus via paracervical injection techniques that are targeted at the cardinal ligament and/or Frankenhauser’s plexus. Conceptually, if large volumes of agent are used, they could capture the fibers from the hypogastric nerve that are encountered about 1 cm from the lateral vaginal fornices. Other strategies designed to provide anesthesia to the uterine corpus include the application of topical anesthetic agents to the endometrial surface via the cervical canal and the injection of anesthesia in the uterine corpus, in particular in the cornual region, the latter to capture fundal innervation from T 10.

There is limited evidence supporting the value of fundal injection directed at the cornual areas where the T 10 nerves are suspected to enter the uterus. A double blind RCT demonstrated that fundal block with only 1 mL of a a 50/50 combination of 3% mepivacaine and 0.5% bupivicaine injected per side, in addition to paracervical and intracervical block reduced the VAS pain score of thermal endometrial ablation score by 1.44 (5.983.01 vs 4.542.86)(21). We are aware of presentations demonstrating no benefit to this approach, however, it seems clear that more investigation is required to demonstrate efficacy using a number of agents and concentrations.

Topical

Data evaluating topical anesthesia have been encouraging but not totally consistent. Topical endometrial anesthesia was investigated in the context of a RCT involving women undergoing hysteroscopically directed endometrial biopsy. The investigators used the inflow channel of the hysteroscopic sheath itself to inject either placebo or a 2% lidocaine solution and demonstrated significantly reduced biopsy-associated pain even though only two minutes transpired between injection and the performance of the procedures (22). There are also RCTs designed to evaluate the use of topical endometrial anesthetic agents that allowed three to five minutes between injection of 2% mepivacaine and performance of the hysteroscopic procedure that have demonstrated a significant reduction in pain (23, 24) and, in one, a reduced incidence of vasovagal reactions (24). Another RCT designed to compare preprocedure misoprostol alone and misoprostol with five mL of 2% intrauterine lidocaine applied two minutes prior to hysteroscopy and aspiration biopsy, all in a cohort of premenopausal women showed a significant reduction in the lidocaine group both for the hysteroscopy (VAS 3.8 to 5.3) and the biopsy(VAS 3.1 to 4.2)(25). However, not all well designed studies have demonstrated this type of outcome (26).

The somewhat inconsistent, but generally supportive results of studies evaluating the utility of topical endometrial anesthesia invite a number of questions. Optimal anesthetic agents, concentrations and delivery vehicles have not been established. There are apparent differences in endometrial innervation that may impact outcomes but it is not yet clear how to determine this prior to a procedure. For example, those with chronic pain syndromes linked to adenomyosis or endometriosis may benefit more from topical agents or may not experience as good a result. The optimal time between between application and maximal anesthetic effect is also unclear but while it is likely at least 3 minutes, it may be more for many women. Furthermore, intrauterine anesthesia may have greater value for procedures requiring contact with the endometrium or removal of endometrial tissue or polyps, as opposed to diagnostic hysteroscopy alone. The performance of appropriately designed clinical research evaluating these variables and more is clearly needed.

Systemic Analgesia

There are systemic agents that have been demonstrated to provide value for the patient without the need for conscious sedation. For example, preprocedural administration of cyclooxygenase (COX) inhibitors have been shown to reduce post procedure pain. A RCT was designed to evaluated a 500 mg oral dose of mefenamic acid given one hour before hysteroscopy and while there was no difference in the pain experienced during the procedure, post procedure pain was less in the treatment group (27).

SUMMARY OF THE EVIDENCE

Currently available evidence regarding the use of local anesthesia for intrauterine procedures is clearly inconsistent. However, several issues must be considered that relate to the design and interpretation of the studies. The myriad potential confounders include differences in populations, procedures, and variations in anesthetic formulation, pKa, concentration, volume and viscosity. In addition, there are a number of nuanced but possibly important differences in administration technique including the time between injection or application and commencement of the procedure. Patient populations vary widely with respect to vaginal parity, menopausal status and other features that may make, for example, unanesthetized cervical dilation painful for some, and painless for others. Procedure duration and the size or volume of any tissue removed from the endometrial cavity may also be factors involved in the amount of pain perceived.

Several investigators have demonstrated very nicely that hysteroscopic procedures can be performed without anesthesia of any sort (28, 29, 30). However, most of the high-quality studies are of diagnostic hysteroscopy (31) and it is clear from others that a substantial number of the women, albeit a minority, experienced substantial procedure-related pain(32). Consequently, it seems reasonable to maintain a critical eye on the evidence and to design studies that better inform us particularly for operative hysteroscopy, but, given the low risk of local anesthetic techniques, to give patients the benefit of the doubt and design approaches that improve their procedure experience.

SUGGESTED UTERINE ANESTHESIA REGIMEN

Approximately 15 years ago, in 2005, we decided to embark upon a program that would move our operating room-based hysteroscopic surgery to an office environment and perform all procedures using local anesthesia. Our experience with office hysteroscopic programs went back to the mid 1980s, but at that time systems were largely used for diagnostic visualization, directed biopsy and removal of small polyps. However, with the advent of improved instrumentation, and the benefit of experience, it became apparent that if we could identify an all-encompassing local anesthetic approach, we could perform the overwhelming majority of procedures under local anesthesia. A systematic review of the literature revealed that we would need to consider a multimodality approach (33), and by 2010 we had managed to perform the entire spectrum of hysteroscopic surgical procedures, in an office procedure room with no systemic agents save COX inhibitors, and with an extremely high degree of success, including a near absence of adverse events (34). And, we were able to train both residents and attending gynecologists and reproductive endocrinologists to achieve similar results. This section describes our approach. section is under construction

Background

There were several considerations in designing a system for uterine anesthesia in the office or clinic setting. First, there was a desire to avoid the use of systemic agents that could or would alter consciousness or otherwise fit into the category of “conscious sedation”. The reasons for this goal included a desire to allow for individuals without ready access to family or friends for transportation. Another goal was reduction of both the direct and indirect costs of institutional hysteroscopic procedures on healthcare systems and patients themselves. The “conscious sedation” approach also mandates some combination of staff and equipment that increase the direct cost of providing the service including pulse oximetry and continuous blood pressure measurement. And one cannot the goals of the hysteroscopic procedure and maintaining both the comfort and the safety of the patient. Our experience of the past 35 years has caused us to strongly that the conscious patient who can see the procedure performed in the intrauterine environment has better insight into the process and confidence regarding the results of the diagnostic or surgical procedure.

The protocol that is presented here is based upon the available evidence but combining o agents with overlapping techniques that take into account the vagina and the somewhat complex innervation of the uterus. While there are a number of components, the total dose of local anesthetics stay well within the allowable range for women. The results of the first group of about 650 cases were published in 2014 and were remarkable for a virtual absence of complications net three transient vasovagal reactions, and a failed access/procedure completion rate of less than 1%(34). Our subsequent unpublished experience that now approaches 3,000 cases has maintained similar outcomes despite an even higher proportion of operative procedures including Type 2 myomectomies, adhesiolysis, metroplasties and the removal of large endometrial polyps.

Figure 2. Multi-site Approach to Uterine Anesthesia - used with permission. The six elements meant to deal with the various potential sources of innervation to the vagina and uterus

The approach combines at least five and sometimes six separate sites (Figure 2). Our primary injectable agent is 1/2% lidocaine that is used with dilute adrenaline or epinephrine (1/200,000 ), a formulation that allows for the use of large injected volumes that stay localized thereby avoiding systemic toxicity, and, at the same time, increasing both neuronal uptake (by lowering pKa and the total dose of anesthetic that can be administered. Topical anesthetic is applied to the vagina, the cervical canal and the endometrial cavity – in our system, the most accessible agent is topical 2% lidocaine gel, but we also use 4% “liposomal” lidocaine cream in the endocervical canal because of a more rapid onset of action. Critical to the success of local anesthesia is something that dentists have done for decades – a commitment to wait an adequate amount of time for the anesthetic agents to reach their maximum effectiveness.

Following hysteroscopic access to the endometrial cavity, we add fundal anesthesia in select procedures such as endometrial ablation and metroplasty using the hysteroscope to direct the injection of ½% lidocaine with 1/200,000 adrenaline either into the septum, or into the fundus, focusing on the periosteal region where the branches that pass through the utero-ovarian ligament would be concentrated.

Basic Technique

Preprocedure

Our protocol asks that patients use a orally administered COX inhibitor for the 48 hours prior to the procedure - sodium naproxen (440 mg every 12 hours) or ibuprofen (600 mg three times per day) are recommended but we have no evidence that these are better than other COX inhibitors. Evidence supporting the 48-hour duration is basically anecdotal as there has been no comparison of this long regimen with the published approach that describes administration of mefenamic acid about an hour prior to the procedure (37). If a patient forgets to take their COX inhibitor, or if oral ingestion is not possible, we typically provide 60 mg of ketorolac intramuscularly about 20-30 minutes prior to the procedure. There are no published data evaluating this approach.

When difficult cervical dilation is anticipated, some prescribe an evening dose of vaginally administered misoprostol (200-400 mg) as described earlier in this section. However, we now rarely use this agent, in part because of the often-troublesome side effects and because we have found that the major reason for “cervical stenosis” is one that is anatomically tortuous. Such anatomy can, in the vast majority of instances, be effectively navigated with relatively narrow hysteroscopic instrumentation under direct vision.

If it is known or suspected that an individual has a very sensitive vaginal epithelium, a circumstance somewhat common in postmenopausal women, not on estrogen, 5 mL of 2% lidocaine gel self-administered with an applicator about one hour prior to the procedure seems highly effective and commensurate with the evidence provided earlier.

Preparing the Patient

Preparation of the patient starts prior to the procedure. Patient information forms, sheets, websites and/or mobile phone applications are useful as a resource and to enhance compliance. We think that it is extremely important that support staff – from reception to nursing and technical support – are all comfortable and knowledgeable in a way that allows them to be reassuring when the inevitable questions arise outside of the examination or consulting room.

The procedure room should be engineered to present a very relaxed atmosphere. Everything possible that can be done to enhance this including color scheme, decorations, comfortable temperature and appropriate music is worthwhile and it should be clean and tidy. It is important that the staff project the aura of competence, and compassion that facilitates a sense of confidence on the part of the patient. There should be an unobtrusively located seat for a significant other, should the patient choose to have one in the room. It is also useful to have this seat positioned in a place that allows the individual to leave, if necessary, without unduly disrupting the procedure. The procedure table or chair should be comfortable, but it should also be easily adjustable for height and attitude. The stirrups should be designed to support the feet and knees in a way that both allows access while being conducive to prolonged positioning in the modified lithotomy position.

Once the procedure is reviewed, informed consent obtained and patient positioned comfortably with feet in the stirrups, an appropriately sized, heated metal speculum, coated with 2% lidocaine gel, is placed in the vagina to expose the cervix. When used this way (without preapplication) there will be minimal initial impact of the lidocaine gel beyond lubrication. However, it is felt that there is clinical impact by 5 minutes into the case, an impression at least supported by the available evidence(8).

Injectable Agent

Our protocol is designed to use a dilute solution of ½% lidocaine with 1/200,000 epinephrine for our injectable agent. This dilution allows a larger volume of anesthetic to be injected for any given dose, and the epinephrine, as described previously, prolongs the anesthetic effect, facilitates transfer of the anesthetic agent into the nerve fiber by increasing local pH, and reduces the amount of systemic absorption thereby increasing the maximum dose from about 4 mg/kg to 7 mg/kg of body weight.

Figure 3. Summary of Local Anesthetic Protocol

The steps of the suggested protocol start with (1) topical vaginal anesthesia with 2% lidocaine gel. (2) A small amount of 1/2% lidocaine with 1/200,000 epinephrine is injected into the cervix anteriorly and posteriorly to allow tenaculum attachment. Then the uterosacral block is placed using the same solution (4). Topical 4% liposomal lidocaine is applied to the cervical canal with cotton tipped applicators. This is followed by installation of 2% lidocaine gel into the endometrial cavity(5). The surgeon waits an appropriate amount of time prior to proceeding. (6) Fundal anesthesia is added if appropriate for the case.

Intra and Paracervical Components

The basic elements of this procedure can be seen in Video 1. The process starts by injecting small amounts of the anesthetic agent into the anterior and posterior aspects of the cervix to reduce the pain associated with tenaculum attachment. A total of 20 mL of ½% lidocaine in 1/200,000 epinephrine solution is drawn into a syringe and a 22-gauge spinal needle is attached. Then the needle tip is placed in proximity to the cervical epithelium and the patient is asked to cough, a maneuver that both appears to reduce the pain related to the injection (35), and simultaneously pushes the cervix against the needle positioned against the epithelial surface. The goal is for the cough to push the uterus caudally so that the needle slightly “impales” the cervix on the needle to the point that the bevel ends up just below the epithelium. This may be assisted by a slight push with the hand holding the syringe-needle assembly. Then, one to three mL of the agent are injected. Because the tenaculum is moved for the paracervical block technique, this process is applied to both the anterior (11-1 o’clock) and posterior aspects (5-7 o’clock) of the exocervix.

Now, a single tooth tenaculum is used to grasp the posterior aspect of the cervix where the anesthetic agent has been injected. The cervix is then retracted anteriorly, a technique that facilitates identification of the attachment of the uterosacral ligaments. These structures can be further enhanced with a rectal swab (large cotton tipped applicator) that is also used to add antiseptic solution to the posterior fornix. Again, using the cough technique, a small amount of the anesthetic solution (about 2 mL) is injected into the vaginal epithelium overlying the uterosacral ligament at its junction with the cervix. Then the needle is advanced into the uterosacral ligament to a depth of 4-5 thereby avoiding the peritoneal cavity – the goal is to capture both the uterosacral ligament and the areolar tissue between the leaves of the broad ligament but avoiding the uterine vessels that are about 9 mm from the fornix. We typically inject approximately 15 to 20 mL of the ½% lidocaine with 1/200,000 epinephrine solution in each side in this fashion, taking care to aspirate prior to injection. Then, the tenaculum is removed from the posterior cervix and affixed to the anterior portion of the cervix for the next step in the procedure.

Topical Agents

Topical anesthetics are applied following the injectable aspect of the protocol. Immediately following completion of the uterosacral block (the type of paracervical block that we perform) and after the tenaculum is applied to the anterior aspect of the cervix, a sterile cotton-tipped applicator coated with 4% liposomal lidocaine cream (eg LMX – 4, Eloquest Healthcare, Ferndale MI) is passed through the external os, and then through cervical canal and the internal os. If this passage is easily accomplished the patient’s tolerance is noted, and the cotton tipped applicator removed. Then the endometrial cavity is filled with 2% lidocaine gel, using a conical-tipped syringe prefilled with either 5 or 10 mL of the lidocaine depending on the anticipated volume of the endometrial cavity – more for parous individuals, less for those who are nulliparous or postmenopausal. For some, particularly those who are obese or who have had uterine surgery such as a cesarean section, the cervix may be too high to allow access with the syringe. In such circumstances, an extension is made using a 6 inch 14 Fr female urinary self-catheter (eg GentleCath™ Convatec, Skillman NJ) that can be easily attached to the distal tip, which is then passed through the exocervix, if necessary with the aid of a packing or sponge forceps. Then the syringe is removed, and two or three sterile cotton-tipped applicators coated with the 4% liposomal lidocaine cream are positioned in the cervical canal with at least one sitting above the level of the external os. The patient is then left for 5 to 15 or more minutes, depending in part upon her response to the cotton-tipped applicator and intracavitary injection, and in part on the complexity of the procedure to be performed.

Fundal Injection

Figure 4. Fundal Block Anesthesia

A 17 Ga oocyte retrieval needle injecting 1/2% lidocaine solution into the tissue around the left tubal ostia. A 4 Fr 23 Ga needle is shown in the inset.

Injection of local anesthesia in the fundus is routinely performed for procedures such as hysteroscopic metroplasty or fundal myomectomy using a needle that can be passed through a 5 Fr operating channel (Figure )(21). Examples of such needles include 4 or 5 Fr cystoscopic injection needles, or the oocyte aspiration needles used to retrieve oocytes for in vitro fertilization. First the needle should be primed and then, under hysteroscopic guidance, the surgeon injects between 3 and 10 mL of ½% lidocaine with 1/200,000 adrenaline directly into the target site. This could be the uterine septum for metroplasty, or in the cornual areas - typically 2-3 mL in each side (Figure )(21).

Protocol Variations, Modifications and Additions Paragraph

Like most protocols, steps have to be modified as appropriate based upon specific features of the patient or procedure that are identified either prior to or during the procedure itself (Figure3).

In the uncommon circumstance where anatomic considerations preclude injection into the uterosacral ligaments, an intracervical injection of about 10 mL of the ½% lidocaine with 1/200,000 adrenaline is placed deeply in each side of the cervix, positioned at about 4-5 o’clock on the left side, and 7-8 o’clock on the right. This approach is designed to attempting to address the area of greatest innervation while continuously moving the spinal needle through the tissue, with periodic aspiration to minimize the risk of significant intravascular injection.

In some instances, the external cervical os is too narrow to accommodate either the cotton-tipped applicator or the prefilled syringe. When this occurs an intrauterine inmination catheter is navigated through the cervical canal into the endometrial cavity and 5 to 10 ml of 2% lidocaine solution injected using an attached syringe. When this approach is not feasible or successful the cervical canal is packed as high as possible using the sterile cotton tipped applicators coated with 4% liposomal lidocaine cream and the patient is left for at least 10 minutes.

Following any of the above, and after the appropriate amount of time has passed, a rigid hysteroscope with a 5 Fr operating channel is used to navigate the canal into the endometrial cavity, if necessary, after dilating the exocervix with rigid dilators. Should cervical canal adhesions be encountered they are transected with hysteroscopic scissors passed through the operating channel. If difficulty persists, we utilize trans abdominal ultrasound to identify the uterus if possible, and to assist in directing the navigation of the cervical canal and the identification of the endometrial cavity. Once within the endometrial cavity the inflow channel of the sheath or hysteroscopic system can be used to allow instillation of 5-10 mL 2% lidocaine, waiting an appropriate time before continuing the procedure.

SUMMARY

We recognize that the protocol described may seem to be “overkill”. However, our published and nonpublished experience reveals that this regimen is safe with the total dose of lidocaine well within the prescribed limits, even in the unlikely event of total absorption of topically administered agents. Many women, and especially those who are vaginally parous undergoing diagnostic hysteroscopy, may not benefit at all from anesthesia, it is difficult to predict response. Consequently, liberal use of local anesthetic techniques should facilitate an increased number of uterine procedures being completed both successfully and comfortably in the office or clinic setting.

REFERENCES

1. Quinn MJ, Kirk N. Differences in uterine innervation at hysterectomy. Am J Obstet Gynecol. 2002;187(6):1515-9; discussion 9-20.

2. Miller EJ, Fraser IS. The importance of pelvic nerve fibers in endometriosis. Health (Lond). 2015;11(5):611-8.

3. Dripps RD, Eckenhoff JE, Vandam LD. Dripps/Eckenhoff/Vandam: Introduction to Anesthesia. In: Longenecker DE, Murphy FL, editors. Introduction to Anesthesia. 8th ed. Philadelphia: Saunders; 1992.

4. Arca MJ, Biermann JS, Johnson TM, Chang AE. Biopsy techniques for skin, soft-tissue, and bone neoplasms. Surg Oncol Clin N Am. 1995;4(1):157-74.

5. Drug facts and comparisons. St Louis: Facts and Comparisons; 2020. https://www.wolterskluwercdi.com/facts-comparisons-online/databases/

6. Krantz KE. Innervation of the human uterus. Ann NY Acad Sci. 1959;75:770-84.

7. Chen HC, Leung SW, Wang CJ, Sun LM, Fang FM, Huang EY, et al. Local vaginal anesthesia during high-dose-rate intracavitary brachytherapy for cervical cancer. Int J Radiat Oncol Biol Phys. 1998;42(3):541-4.

8. Keskin AE, Onaran Y, Duvan IC, Simavli S, Kafali H. Topical anesthetic (lidocaine-prilocaine) cream application before speculum examination in postmenopausal women. Journal of minimally invasive gynecology. 2012;19(3):350-5.

9. Vercellini P, Colombo A, Mauro F, Oldani S, Bramante T, Crosignani PG. Paracervical anesthesia for outpatient hysteroscopy. Fertil Steril. 1994;62(5):1083-5. Paragraph

10. Lau WC, Lo WK, Tam WH, Yuen PM. Paracervical anaesthesia in outpatient hysteroscopy: a randomised double-blind placebo-controlled trial. British journal of obstetrics and gynaecology. 1999;106(4):356-9. Paragraph

11. Cicinelli E, Didonna T, Schonauer LM, Stragapede S, Falco N, Pansini N. Paracervical anesthesia for hysteroscopy and endometrial biopsy in postmenopausal women. A randomized, double-blind, placebo-controlled study. J Reprod Med. 1998;43(12):1014-8.

12. Giorda G, Scarabelli C, Franceschi S, Campagnutta E. Feasibility and pain control in outpatient hysteroscopy in postmenopausal women: a randomized trial. Acta obstetricia et gynecologica Scandinavica. 2000;79(7):593-7.

13. Titapant V, Chawanpaiboon S, Boonpektrakul K. Double-blind randomized comparison of xylocaine and saline in paracervical block for diagnostic fractional curettage. J Med Assoc Thai. 2003;86(2):131-5.

14.Tangsiriwatthana T, Sangkomkamhang US, Lumbiganon P, Laopaiboon M. Paracervical local anaesthesia for cervical dilatation and uterine intervention. The Cochrane database of systematic reviews. 2013;9:CD005056.

15. Ferry J, Rankin L. Transcervical resection of the endometrium using intracervical block only. A review of 278 procedures. Aust N Z J Obstet Gynaecol. 1994;34(4):457-61.