Small-Caliber Endoscopy

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Chapter 10 Small-Caliber Endoscopy

Christopher J. Gostout

Chapter Outline

Introduction 101
Small-Caliber Endoscopy Insertion Techniques 101
Unsedated Small-Caliber Upper Endoscopy 103

Technical Feasibility of Unsedated Small-Caliber Endoscopy 103
Tolerability of Unsedated Small-Caliber Endoscopy 104
Safety of Unsedated Small-Caliber Endoscopy 105
Adequacy of Unsedated Small-Caliber Endoscopy and Biopsy 106
Cost-Effectiveness of Unsedated Small-Caliber Endoscopy 107
Therapeutic Applications for Small-Caliber Endoscopy 107
Conclusion 109

imageVideo related to this chapter’s topics: Small-Caliber Endoscopy

Introduction

Small-caliber endoscopy has selective appeal. Sedation may be responsible for a substantial proportion of the morbidity and mortality of endoscopic procedures. The opportunity to perform diagnostic endoscopy without sedation can overcome the issues relative to sedation, especially in high-risk patients. The administration of sedatives increases the preprocedure preparation, total procedure, and postprocedure recovery times. Finally, the “sedationless” argument gains strength with regard to lifestyle impact, allowing the patient to minimize time away from work or family and eliminating the need for an accompanying responsible person. Despite its potential safety and cost-effectiveness, however, the practice of unsedated endoscopy with small-caliber endoscopes has not gained wide acceptance. Many factors may be responsible, including inadequate evidence for efficacy, poor patient acceptance, lack of physician incentives, and limited opportunities for training.

Small-caliber endoscopy has other practical uses. Patients who may be predictably intolerant of endoscopy with sedation, such as young patients, are potential candidates for this option. Small-caliber endoscopy offers a dramatically reduced procedure stress for patients who have fragile cardiopulmonary disease. The small-caliber endoscope provides an effective and well-tolerated option for the placement of transnasal feeding tubes and the placement of jejunal extensions via an existing percutaneous feeding gastroscopy site.1–3 Patients with high-grade esophageal strictures with existing percutaneous feeding gastrostomy may have primary or rendezvous attempts at dilation with placement of guidewires using a small-caliber endoscope via the gastrostomy site.4,5

Small-Caliber Endoscopy Insertion Techniques

Small-caliber upper endoscopy can be performed either transnasally or perorally (Fig. 10.1). Transnasal endoscopy is feasible with endoscopes measuring 6 mm or less in outside diameter. Table 10.1 summarizes specifications of small-caliber endoscopes used in the reviewed studies and other endoscopes that are commercially available. Both videoesophagogastroduodenoscopes and esophagoscopes are currently available. Videoesophagogastroduodenoscopes have a working length of 1030 to 1330 mm, and esophagoscopes have a working length of only 600 mm. The outer diameter of videoesophagogastroduodenoscopes is between 5.1 mm and 6 mm. Esophagoscopes have an outside diameter between 3.1 mm and 4 mm. The relative outside diameters of small-caliber pediatric and conventional esophagogastroduodenoscopes are shown in Fig. 10.2A. Some esophagogastroduodenoscopes allow right and left and up and down angulation, whereas others provide only up and down angulation (Fig. 10.2B).

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Fig. 10.1 Nasal passage anatomy. Small-caliber endoscope is passed directly back along the floor of the nasal passage, along the medial septum, avoiding the turbinates, with flexion of the tip down into the posterior pharynx (line arrow).

Table 10.1 Fiberoptic and Video Small-Caliber Endoscopes Available for Unsedated Upper Endoscopy

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Fig. 10.2 Small-caliber upper endoscopes. Distal ends of a small-caliber, pediatric, and conventional esophagogastroduodenoscope are shown (A) along with the handle of a small-caliber endoscope with only one ratchet for up and down control (B).

Careful patient selection and preparation are of utmost importance. Uncooperative patients and young patients with a high preprocedure anxiety level are not well suited for unsedated procedures. Elderly patients tolerate the examination extremely well—so well that in our institution we contemplated offering this exclusively for patients 80 years or older undergoing diagnostic endoscopy. Because the tolerability of the procedure is related to preprocedure anxiety, the procedure must be explained clearly before intubation.

Topical anesthesia in the form of a spray or jelly is useful before endoscope insertion. The application of 2% lidocaine jelly into the more patent nostril as determined by visual inspection is recommended for this approach to topical anesthesia. Pharyngeal anesthesia is also recommended. Local vasoconstrictors may also be beneficial, especially when a 6-mm diameter instrument is inserted transnasally. If a 4-mm or smaller caliber endoscope is used, a local vasoconstrictor may be of marginal value to aid insertion, but it may minimize epistaxis.

The procedure can be performed either in the standard left lateral decubitus position for conventional endoscopy or in the upright position (Fig. 10.3). Whether the upright position decreases the aspiration risk is unknown. The transnasal procedure should be performed with minimal air insufflation. The endoscope should be inserted slowly and gently, keeping the insertion tube of the endoscope straight such that it passes along the floor and septum of the nasal cavity and it does not migrate upward and laterally into turbinates interrupting passage, causing pain, and inducing bleeding. Slow progressive insertion with flexion of the endoscope tip over the base of the tongue is recommended for unsedated peroral examinations. Vigorous movements of the endoscope cause greater nasal discomfort with the transnasal route and more gagging with the peroral approach. During the procedure, conversing with the patient and pointing out findings on the video monitor reassure patients and may improve tolerability and reduce discomfort.

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Fig. 10.3 Patient is shown undergoing transnasal small-caliber esophagogastroduodenoscopy in the upright position.

Unsedated Small-Caliber Upper Endoscopy

The impact of unsedated small-caliber endoscopy on the everyday practice of esophagogastroduodenoscopy (EGD) is complex. There are no data from large randomized controlled trials. Although lower procedure cost and complication rate favor unsedated EGD, poor patient tolerance, suboptimal visualization, and failure to complete the procedure could increase the cost of upper endoscopy secondary to repeated examination by sedated EGD. Analyses of the few existing randomized controlled studies provide sufficient evidence that unsedated small-caliber upper endoscopy is feasible and tolerable in select patient groups. Most evidence suggests, however, that small-caliber endoscopy is slightly less sensitive.

There are conflicting reports regarding the transnasal approach and whether or not it is preferred over the peroral route. Based on a questionnaire provided to patients undergoing endoscopy at our outpatient units, patient preference is actually for peroral intubation. This preference has been well appreciated within our motility practice, which for decades has performed esophagogastroduodenal motility via a peroral catheter approach. Data are insufficient regarding the safety of unsedated small-caliber endoscopy compared with sedated conventional endoscopy. Finally, the cost-effectiveness of unsedated small-caliber endoscopy is yet to be determined. With that in mind, the following sections summarize the literature addressing the various aspects of unsedated small-caliber endoscopy.

Technical Feasibility of Unsedated Small-Caliber Endoscopy

Feasibility of unsedated small-caliber endoscopy is mainly a subjective measure defined by the endoscopist. It can be affected by many factors, including the diameter of the small-caliber endoscope, endoscope maneuverability, image quality, patient tolerability, and the skills of the endoscopist. Feasibility of unsedated endoscopy is particularly linked to tolerance, which is discussed in the next section. In the crudest sense, technical feasibility represents the successful completion of the intended procedure by intubating the duodenum if an EGD is being performed or intubating the stomach if esophagoscopy is being done. Several investigators have reported the feasibility of transoral or transnasal unsedated EGD.6–18 Most of these studies have not been prospective randomized controlled trials. The patient populations have been either small in size or not representative of the general U.S. population. Studies addressing the feasibility of EGD that warrant attention are described next.

Wilkins and coworkers6 randomly assigned 72 patients to undergo either unsedated small-caliber EGD or sedated conventional EGD. Despite a highly selected and motivated U.S. Air Force community population, only 29 of the 33 patients (88%) had a complete unsedated small-caliber EGD. In another controlled study, Mulcahy and coworkers7 compared the feasibility of unsedated small-caliber EGD with unsedated conventional EGD in 322 patients. EGD was completed in 160 of the 163 patients (98%) undergoing unsedated EGD with a 6-mm gastroscope compared with 145 of the 159 patients (91%) undergoing unsedated EGD with a 9.8-mm gastroscope. These investigators subsequently reported 39 (8%) failures in a prospective study of 508 patients undergoing routine unsedated gastroscopy.8 Failure was associated with larger scope diameter (>9 mm), higher preprocedure anxiety, and younger age.

Ristikankare and colleagues9 randomly assigned 180 patients undergoing EGD to receive intravenous (IV) midazolam, IV saline, or no IV access. Although the procedure was perceived “less difficult” in the IV midazolam group compared with the IV saline group, the difference was not statistically significant. The power to detect differences between the three groups was not determined in this study. The small patient population and the lack of validated criteria to assess the difficulty of an EGD limit the utility of the evidence.

The feasibility of unsedated small-caliber EGD was also assessed as part of the multiphase Mayo Clinic Rochester study of a select group of highly motivated patients and volunteers.10 The second portion of the duodenum was reached in 20 sedated and 20 unsedated volunteers in this prospective, nonrandomized study. Among the patients, 50 subjects successfully underwent sedated small-caliber EGD followed by sedated conventional EGD, and 38 of 40 patients underwent successful unsedated small-caliber EGD followed by sedated conventional EGD. Overall, the technical feasibility was not significantly affected by sedation in this study. A type II error (failure to detect a significant difference when there is a difference) cannot be ruled out, however, because the sample size to detect a significant difference was not calculated.

Investigators have also studied the feasibility of unsedated transnasal small-caliber EGD. Saeian and coworkers11 showed that unsedated transnasal esophagoscopy with a 5.3-mm gastroscope was feasible in 15 cirrhotic patients. The study was uncontrolled, and the population was very small. Zaman and colleagues13 compared peroral and transnasal approaches for EGD with the same small-caliber instrument using a prospective randomized crossover study design. Of 105 patients, 60 (57%) agreed to undergo unsedated small-caliber EGD. Peroral unsedated EGD was feasible in 34 of 35 (97%) patients, including 4 who failed transnasal EGD and were crossed over. Unsedated transnasal EGD was feasible in only 25 of 29 (86%) patients. The statistics were not reported, and a sample size based on a study hypothesis was also not calculated before study initiation.

Campo and coworkers14 randomly assigned 181 Spanish patients to undergo transnasal small-caliber EGD or peroral conventional EGD. Insertion failed in six (3.3%) patients; four had been randomly assigned to the transnasal route and two to the peroral route. In a prospective randomized trial in Australia, Craig and colleagues17 compared the feasibility of unsedated transnasal with unsedated peroral small-caliber EGD. A complete examination was feasible in 74 of the 84 (88%) transnasal and 85 of the 86 (99%) transoral procedures (P = .004).

Dumortier and coworkers18 reported that unsedated transnasal EGD was feasible in 1033 of 1100 (94%) patients studied prospectively at three French medical centers. Failures were mainly due to the inability to insert the small-caliber endoscope (62.7%). Other reasons for failure included patient refusal and nasal pain. In their prior study published in 1999, the same investigators showed that unsedated transnasal EGD was feasible in 82% of the study population and was associated with less nausea and choking.19 The feasibility of transnasal small-caliber EGD was initially assessed in 100 patients in this two-phase study; 150 patients were then randomly assigned to undergo peroral conventional EGD with a 9.8-mm videoendoscope, peroral small-caliber EGD with a 6-mm videoendoscope, or transnasal small-caliber EGD with a 6-mm videoendoscope.

The evidence that supports the feasibility of unsedated upper endoscopy compared with sedated endoscopy is limited. The randomized studies that have been reviewed failed to specify the study hypothesis and to calculate a sample size before study initiation. These studies may have failed to detect a difference because of a type II error. The studies have also used different caliber instruments, and there is some evidence suggesting that the feasibility of an unsedated examination may be better with smaller diameter instruments. None of the studies had sufficient power to examine whether unsedated endoscopy is feasible for all indications. Comparative studies comparing transnasal and peroral approaches have given variable results. However, the weight of the evidence suggests that transnasal intubation may not be feasible in all patients.

Tolerability of Unsedated Small-Caliber Endoscopy

The tolerability of unsedated small-caliber esophagoscopy or EGD is of utmost importance. It directly affects patient or physician acceptance, examination adequacy, and technical feasibility. Many studies have measured the tolerability of unsedated upper endoscopy by evaluating specific symptoms, such as gagging, choking, pain, and discomfort, on a Likert scale. Tolerability of unsedated endoscopy varies considerably across countries and patient populations. Although unsedated upper endoscopy may be considered the norm in some countries, the idea may not be appealing to U.S. endoscopists and U.S. patients. Even regional differences may be noted within the United States.

Tolerability is a complex variable, which is likely affected by numerous patient-related and operator-related factors, including patient education, prior endoscopic experience, preprocedure anxiety, patient age, patient gender, endoscopist skill, and technical performance of the endoscope. A prohibitively large and diverse patient population would be required to determine how all of these factors affect the tolerability and acceptance of unsedated endoscopy. Catanzaro and coworkers20 evaluated patient tolerability of unsedated endoscopy with a 4-mm esophagoscope. This study enrolled 51 patients; 30 patients underwent an unsedated procedure. Of these patients, 18 preferred the peroral route, and 12 preferred the transnasal route. Patient tolerability and acceptability of unsedated esophagoscopy with the 4-mm esophagoscope compared favorably with a historical group of patients examined with a 3-mm esophagoscope.

In an earlier study, Catanzaro and colleagues21 assessed the use of a 3.1-mm, battery-operated esophagoscope in an unsedated procedure. Examination with the battery-operated esophagoscope was performed in 98 patients. Of the 56 patients undergoing an unsedated examination, 43 preferred the peroral approach. Although the endoscopist’s perception of patient discomfort was not significantly different, the patients undergoing unsedated small-caliber esophagoscopy reported significantly more choking, pain, and overall discomfort with the 3.1-mm, battery-operated esophagoscope.

Faulx and coworkers22 approached 98 patients to undergo unsedated esophagoscopy with a 3.1-mm esophagoscope before conventional EGD. Only 46% of the 52 patients participating in the study preferred unsedated 3.1-mm esophagoscopy over conventional EGD in the future. Of patients, 16 chose the peroral approach, and 36 chose the transnasal approach. Patients who chose the peroral route were more likely to prefer unsedated small-caliber endoscopy with the 3.1-mm esophagoscope compared with the transnasal approach (58% vs. 23%).

Saeian and colleagues11 performed sedated conventional EGD following unsedated small-caliber EGD and reported no significant difference in choking, discomfort, and sore throat in a population of 15 cirrhotic patients. In contrast, Wilkins and coworkers6 reported increased gagging and choking in the 33 patients randomly assigned to undergo unsedated small-caliber EGD compared with the 39 patients who underwent sedated conventional EGD. However, most patients tolerated unsedated small-caliber EGD.

A prospective study in the United States found that only 52 of 98 patients (53%) approached agreed to undergo unsedated esophagoscopy with a 3.1-mm esophagoscope followed by sedated EGD.22 Although one may argue that the willingness to undergo unsedated endoscopy may be hampered by undergoing tandem endoscopies, this is one of the few well-designed studies to address the impact of unsedated endoscopy on the practice of EGD. Of the 52 patients who underwent both procedures, only 46% preferred unsedated EGD. Patients who had transnasal esophagoscopy were less likely to prefer an unsedated procedure in the future compared with patients who underwent peroral esophagoscopy (23% vs. 58%). Similarly, Zaman and colleagues23 reported that 19 (31%) of 62 patients asked to undergo unsedated 6-mm transoral EGD followed by sedated transoral conventional EGD refused. Of the 43 patients who agreed to undergo unsedated small-caliber EGD, 30 (70%) were willing to have unsedated small-caliber EGD in the future.

A prospective randomized controlled trial from a center in the United Kingdom that routinely performs unsedated endoscopies concluded that endoscopists found unsedated examinations easier, but patients reported significantly greater comfort with sedation.24 Another trial from the United Kingdom that studied 62 elderly patients reported that an equal number of patients undergoing sedated or unsedated EGD described the procedure as “mildly unpleasant.”25 Of the patients who underwent unsedated EGD, 73% did not wish to be sedated for future EGD. Froehlich and colleagues26 randomly assigned 200 European patients to receive IV midazolam with lidocaine spray, IV placebo with lidocaine spray, IV midazolam with placebo spray, or IV placebo with placebo spray and showed that tolerability, assessed on a visual analogue scale, was significantly improved in patients who received IV sedation.

One major difficulty with the interpretation of the studies comparing the tolerability of unsedated endoscopy with sedated procedures is that benzodiazepines affect recall. The timing of when the patient is questioned may affect the response to the questions. The only prospective controlled trial that compared two unsedated procedures found that patients reported less discomfort when peroral EGD was performed with a 6-mm endoscope compared with a 9.8-mm instrument.7 Sedation during future examination was requested by 14% of subjects who underwent examination with a 6-mm endoscope compared with 31% of patients examined with a 9.8-mm endoscope.

A few studies have compared the tolerability and acceptance of unsedated transnasal and peroral approaches. In a randomized U.S. trial of unsedated peroral versus transnasal small-caliber EGD, Zaman and coworkers13 determined that 89% of the patients undergoing peroral EGD and 69% of the patients undergoing transnasal EGD were willing to have unsedated small-caliber EGD in the future. A smaller U.S. study of 24 patients who had undergone transnasal unsedated EGD followed by conventional EGD concluded that transnasal EGD was more acceptable.15 However, a randomized Australian study of 170 patients found no significant difference in tolerability of unsedated small-caliber EGD with either route.17 Dumortier and colleagues18 reported that 95% of 1033 French patients who successfully underwent unsedated small-caliber transnasal EGD were willing to repeat the procedure. Of the 377 patients who had previously undergone unsedated transoral EGD, 91% preferred the transnasal route.

Most of the literature suggests that unsedated endoscopy is not as tolerable as sedated endoscopies. The evidence in support of a transnasal approach to improve procedure tolerability is inconclusive because various studies have reported contradictory results. Patients who have successfully completed unsedated endoscopy seem to have moderate acceptance of the procedure. For reasons not completely understood, U.S. patients may be particularly unwilling to undergo unsedated endoscopy.

Safety of Unsedated Small-Caliber Endoscopy

One of the arguments for advocating unsedated procedures is that the morbidity and mortality of endoscopic procedures are largely related to sedation. The evidence to support this allegation is limited, however. The practice of sedated endoscopy is very safe, and complications are uncommon. The incidence of serious cardiorespiratory complications in an American Society for Gastrointestinal Endoscopy (ASGE)/U.S. Food and Drug Administration (FDA) collaborative study of 21,011 procedures was 5.4 per 1000 cases, and the incidence of death was 0.3 per 1000 cases.27 A large retrospective German study found that the overall complication rate associated with sedated EGD was 0.009%.28

Because of the low complication rate of sedated EGD, any study to determine whether unsedated EGD is safer would require an extremely large patient population. The safety of unsedated EGD has been addressed in several small studies. Limited studies have reported no serious complications in 60 patients5 and 170 patients17 who underwent unsedated procedures. Epistaxis is unique to transnasal EGD and can occur in one of five patients29; this is not surprising given that insertion of a soft small-bore nasogastric tube may result in epistaxis. The largest prospective study of unsedated transnasal EGD revealed epistaxis in 2.3%, nasal pain in 1.6%, and vasovagal reactions in 0.3% of 1100 consecutive patients participating in the study at three French centers. Much larger studies of unsedated EGD are needed to determine a true cardiorespiratory complication rate of the procedure. Cost prohibits the performance of such a large prospective randomized comparative study on the safety of unsedated and sedated EGD. Although it seems that transnasal unsedated EGD is associated with an increased rate of minor complications (epistaxis) compared with peroral EGD, larger comparative studies with ultrathin endoscopes are required. In the absence of data from large prospective studies, the currently available safety data originate from small prospective or retrospective studies.

Adequacy of Unsedated Small-Caliber Endoscopy and Biopsy

The data on the adequacy of examinations performed using small-caliber endoscopes are even more limited. Image quality, suctioning ability, adequacy of tissue sampling, and ability to perform therapeutic maneuvers are among the main determinants of “adequacy.” The specifications of several small-caliber upper endoscopes are listed in Table 10.1. Most commercially available small-caliber endoscopes incorporate video charge-coupled devices technology, although some studies have been performed with fiberoptic instruments. The outside diameter of these endoscopes is 5 to 6 mm, approximately half the diameter of a conventional upper endoscope (see Fig. 10.2A). The esophagoscopes have a working length of 600 mm to allow intubation of the stomach. Some are battery-operated, and none allow biopsies. A thinner insertion tube may be too flexible, limiting passage through the pylorus and intubation of the second portion of the duodenum. Some manufacturers have marketed small-caliber endoscopes that have only unidirectional up-and-down tip deflection (see Fig. 10.2B), whereas others have bidirectional up-and-down and right-and-left tip deflection similar to conventional instruments. The accessory channel of small-caliber esophagogastroduodenoscopes is generally 2 mm; this limits the size of the biopsy specimens that can be obtained and the ability to perform therapeutic interventions. The smaller diameter of the channels could also impair the ability to aspirate blood, secretions, and debris and the ability to wash the lens. A sample image of the gastroesophageal junction as viewed by a small-caliber endoscope is shown in Fig. 10.4, and a brief normal transnasal examination is presented as a video clip.image

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Fig. 10.4 Endoscopic image of a normal squamocolumnar junction as viewed by a videoesophagogastroduodenoscope.

Wildi and coworkers30 and Catanzaro and colleagues20,21 addressed the accuracy of small-caliber esophagoscopes. Wildi and coworkers30 assessed the diagnostic accuracy of sedated esophagoscopy performed by a nurse practitioner using a 4-mm esophagoscope compared with sedated conventional EGD performed by an experienced gastroenterologist. There were 40 patients who underwent tandem procedures in a blinded fashion. For all esophageal lesions, the sensitivity and specificity of the examination by the nurse practitioner were 75% and 98%. All four Schatzki rings were missed.30 In their study of 51 patients undergoing esophagoscopy using the 4-mm esophagoscope, Catanzaro and colleagues20 reported sensitivity, accuracy, and specificity of 91%, 98%, and 99% for detecting all esophageal lesions. The first 24 patients underwent endoscopy using the battery-operated fiberoptic esophagoscope, and 27 patients were examined with the 4-mm videoesophagoscope. In an earlier study, Catanzaro and coworkers21 reported that the accuracy of esophageal examination with a 3.1-mm endoscope is substantially inferior to conventional EGD. The sensitivity for detecting Barrett’s esophagus, esophageal tumors, and esophageal varices was 54.5%, 66.7%, and 80%. Optical quality was reported as less than 4 on a scale of 1 to 5 in 42% of the cases.

In the study of Dumortier and colleagues,18 endoscopic biopsy specimens, obtained in 457 subjects undergoing a transnasal examination, were considered “sufficient.” Four esophageal cancers and one gastric cancer were correctly diagnosed by biopsy. Although this is the largest study addressing the adequacy of samples obtained at the time of unsedated transnasal EGD, this outcome was not the primary or even secondary goal of the study. Criteria for determining sample adequacy were not defined. Zaman and coworkers18 reported that unsedated peroral small-caliber EGD with a video instrument missed 5 of 59 lesions identified by conventional EGD in 62 patients, yielding an accuracy of 92%. The optical quality of the images was rated as good in 84%, 65%, and 78% of the subjects when examining the esophagus, stomach, and duodenum. In a similar study of unsedated transnasal EGD, Dean and colleagues15 found a sensitivity of 89% and a specificity of 97% using a fiberoptic instrument.

In the only study examining the effect of sedation and endoscope caliber, Sorbi and coworkers10 showed that the accuracy for major endoscopic findings was 96% for the 50 patients who underwent sedated transoral small-caliber EGD and 97% for the 40 patients who underwent unsedated transoral small-caliber EGD. The view was particularly limited because of the inability to aspirate secretions and clear bubbles rapidly. These results suggest that caliber, and not sedation, may be the primary factor determining the accuracy of unsedated small-caliber endoscopy. The 4-mm diameter may be the lower limit for upper endoscopes to maintain adequate image quality.

Regardless of whether a videoendoscope or a fiberoptic endoscope is used, studies comparing small-caliber upper endoscopy with conventional upper endoscopy have uniformly reported that the smaller caliber instruments have a slightly lower accuracy. Lesions missed by small-caliber instruments tend to be mild esophageal stenoses or lesions located in the second portion of the duodenum. Although small-caliber endoscopes apparently are accurate for detecting common lesions, the studies have not addressed the accuracy of small-caliber endoscopy for detecting subtle rare mucosal abnormalities such as early malignancies. There is also insufficient evidence whether biopsy specimens obtained by small-caliber endoscopes are adequate for detecting dysplasia in Barrett’s esophagus.

Cost-Effectiveness of Unsedated Small-Caliber Endoscopy

Cost may be the major impetus behind the practice of unsedated endoscopy. Elimination of sedation may significantly reduce the cost of endoscopy. However, the total expense of unsedated endoscopy must be studied in view of its impact on the everyday practice of EGD. Unsedated small-caliber endoscopy can result in savings only if the general population finds it acceptable and if most unsedated examinations are adequate and a repeat examination under sedation is not required. The impact of unsedated endoscopy on the cost of EGD has been evaluated only in a few studies. In a case-control study, Gorelick and colleagues31 assessed the potential cost savings associated with unsedated small-caliber EGD in 16 patients undergoing unsedated transoral small-caliber EGD matched for age, gender, indication, and procedure day with a control group of 16 patients who underwent sedated conventional EGD. The mean procedure room time was 16.3 minutes for unsedated small-caliber EGD and 34.9 minutes for sedated conventional EGD (P < .0005). The mean recovery room time was 9.0 minutes for unsedated small-caliber EGD and 41.3 minutes for sedated conventional EGD (P < .00001). The mean cost for unsedated small-caliber EGD was $462 and was considerably lower than the mean cost of sedated conventional EGD, which was reported as $587 (P < .0006).

In a controlled study, Wilkins and coworkers6 randomly assigned 72 patients to undergo either unsedated small-caliber EGD or sedated conventional EGD. The procedure time (mean ± standard error of the mean) for the 33 patients who underwent unsedated small-caliber EGD was 21.5 ± 2.3 minutes, whereas the procedure time for the 39 patients who underwent sedated conventional EGD was 55.4 ± 2.3 minutes. Without performing a formal cost analysis, the investigators suggested that unsedated small-caliber EGD performed by primary care physicians could increase access while decreasing the cost of upper endoscopy. Bampton and colleagues32 compared unsedated transnasal EGD with sedated transoral EGD. The mean procedure times of 15 minutes for the unsedated procedure and 20 minutes for the sedated procedure were not significantly different. However, the mean recovery time was 7 minutes for the unsedated transnasal examination compared with 37 minutes for the transoral sedated EGD, emphasizing the shorter recovery time when no sedation is administered. A formal cost-effectiveness analysis of unsedated versus sedated endoscopy that accounts for variations in the patient population, patient acceptance, completion rates, and diagnostic accuracy is yet to be performed to determine the utility of this approach in the daily practice of upper endoscopy.

Therapeutic Applications for Small-Caliber Endoscopy

The following are common and practical applications:

1 Guidewire placement and dilation of pharyngeal and cervical esophagus in patients who have undergone cancer surgeries with and without radiation
2 Guidewire placement and dilation of high-grade esophageal strictures
3 Transnasal guidewire and nasogastric or nasojejunal tube feeding tube placement (Fig. 10.5)
4 Percutaneous transgastric conversion of a gastric feeding tube to a jejunal extension (Fig. 10.6)
5 Retrograde percutaneous transgastric intubation of a feeding gastrostomy for access to the esophagus in the setting of a high-grade stricture at any level with placement of a guidewire to enable dilation
6 Retrograde percutaneous transgastric intubation of a feeding gastrostomy for rendezvous access to near-total esophageal stricture using simultaneous peroral endoscopy (Fig. 10.7)
7 Percutaneous evaluation of persistent long-standing fistulas with closure using injected fibrin sealants or cyanoacrylate glues
8 Percutaneous entry via cholecystostomy tract or transhepatic tract for stone clearance33
9 Percutaneous evaluation and initiation of drainage procedures for abdominal and retroperitoneal abscesses (Fig. 10.8).
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Fig. 10.5 Illustration of small-caliber endoscope passed transnasally into postbulbar duodenum with guidewire placement beyond the ligament of Treitz (using supplemental fluoroscopy).

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Fig. 10.6 Illustration of small-caliber endoscope passed via an existing percutaneous gastrostomy feeding tube site into the duodenum to the ligament of Treitz with guidewire placed well into the jejunum.

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Fig. 10.7 Illustration of small-caliber endoscope passed via an existing percutaneous gastrostomy feeding tube site into the esophagus. There is simultaneous placement of a standard endoscope perorally down to the level of esophageal obstruction with a guidewire extended beyond the endoscope to probe a potential lumen site.

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Fig. 10.8 Illustration of small-caliber endoscope passed via a right flank percutaneous tract into the right perinephric space exploring residual necrotic material and eventually directing more accurate catheter drainage. Necrotic material is the result of extensive organized necrosis, loculated contiguous to the kidney, subsequent to acute pancreatitis.

Small-caliber endoscopes nearly uniformly provide 2.0-mm working channels. These do not prevent the use of standard 0.035-inch guidewires. The longer small-caliber endoscopes (e.g., Olympus N180 series 100 cm) are perhaps more advantageous for placement of jejunal feeding tubes. These instruments offer only up-and-down tip deflection. The insertion tube is soft enough to enable torquing movements that conveniently replace the left-and-right tip deflection options. Small-caliber endoscopy via an existing percutaneous gastrostomy site can be performed without sedation.

As noted earlier, patients with persistent well-organized abscesses and collections of necrotic material, in either the peritoneal or the retroperitoneal spaces, who have had percutaneous catheter efforts performed for the purpose of drainage and resolution typically have well-established fistulas into the persistent cavity and collection. The small-caliber endoscope can provide useful identification of unaccessed collections and facilitate their drainage by visually directing catheter placement for drainage or dilating the percutaneous fistulas via guidewire placement, allowing larger endoscopes to be passed for débridement. This is a very unique application that can provide a successful outcome for difficult management situations. Passage of small-caliber endoscopes percutaneously via established fistula tracts into either the liver or the gallbladder for stone clearance has been well established.

Conclusion

The practice of gastrointestinal endoscopy is constantly evolving. Unsedated small-caliber upper endoscopy is intuitively appealing, and sufficient data exist to support the feasibility of unsedated small-caliber endoscopy in selected patients. Adequate data suggest that the sensitivity of small-caliber endoscopes may be slightly less than conventional EGD. Current literature lacks sufficient evidence, however, to provide guidelines on how to select the suitable patient population and whether or not unsedated endoscopy results in cost savings without significantly compromising comfort. There are more useful applications of the small-caliber endoscope, to enable sedated examinations in poorly tolerant or fragile patients and, even more so, to facilitate feeding tube placement, resolve complex strictures, and resolve abdominal abscesses and necrosis collections.

References

1 Wildi S, Gubler C, Vavricka S, et al. Transnasal endoscopy for the placement of nasoenteral feeding tubes: does the working length of the endoscope matter? Gastrointest Endosc. 2007;66:225-229.

2 Adler D, Gostou C, Baron T. Percutaneous transgastric placement of jejunal feeding tubes with an ultrathin endoscope. Gastrointest Endosc. 2006;55:106-110.

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