Introduction
The aim of transoral treatment of Zenker diverticulum is to divide the cricopharyngeal
muscle contained in the septum, i.e, the posterior common wall separating the pouch
from the esophagus. The transoral approach through rigid endoscopy (with stapler,
C02-laser, harmonic scalpel, or Ligasure) or through flexible endoscopy (mainly with
electrocautery) has proven safe and effective in expert centers [1]
[2]
[3].
Today, Thulium laser is extensively used in urology because it allows optimal tissue
vaporization, precise tissue ablation with limited lateral thermal spread (0.1 – 0.3 mm),
and controlled tissue penetration [4]. To date, only experimental animal studies and few human endoscopic applications
in the upper gastrointestinal tract have been reported [5]
[6].
We hypothesized that the technical characteristics of the Thulium laser could allow
safe and effective division of the septum in Zenker diverticulum through flexible
endoscopy. We report the first human application of Thulium laser in a small cohort
of patients with Zenker diverticulum.
Patients and methods
Thulium laser septum division was performed via flexible endoscopy in consecutive
symptomatic patients referred to our institution for primary or recurrent Zenker diverticulum.
The Internal Review Board deemed the study exempt from ethical approval. Primary study
outcomes were feasibility and safety of the procedure. Patient demographics and relevant
clinical data were collected prospectively. Dysphagia and regurgitation were scored
on a scale from 1 to 4, and presence of respiratory symptoms was recorded [7]. The endoscopic procedure was performed in the operating room under general anesthesia
with endotracheal intubation. Intravenous antibiotic prophylaxis was given 30 minutes
before the procedure. To improve exposure and stabilize the septum during the procedure,
either a transparent cap (Olympus), a flexible overtube (Cook), or the Weerda diverticuloscope
were used. The laser system used was the Opera (Quanta System SPA, Varese, Italy),
emitting a 1.9-μm Thulium wavelength radiation. A continuous laser configuration and
an emission power of 5 to 16 W were chosen. Using 272 and 365 μm optical fibers in
a non-contact mode, laser incision was performed in the midline of the septum until
cricopharyngeal muscle fibers were encountered and a V-shaped myotomy was completed
under visual control ([Fig. 1]). A chest film and a gastrographin swallow study were performed on postoperative
Day 1 before oral feeding. Patients were scheduled for a follow-up visit at 1 and
3 months after surgery.
Fig. 1 Endoscopic cricopharyngeal myotomy with Thulium laser. a The 272 fiber is out of the operating channel of the endoscope and the laser beam
is directed to the septum. b The cricopharyngeal muscle has been exposed after mucosal incision.
Results
Between May and June 2017, 5 consecutive patients with a median age of 81 years (range
43 – 84) were treated. All patients complained of dysphagia and regurgitation; chronic
cough was reported by two patients. Two patients presented with a recurrent symptomatic
diverticulum after previous transoral septum stapling. The median diverticulum size
was 3 cm. All procedures were performed under general anesthesia. In all patients,
complete division and separation of the septum was achieved. No bleeding/oozing occurred,
and there was no need for adjunctive electrocautery devices to complete the procedure
([Video 1]). Median operative time was 110 minutes (range 60 – 125 min). The initial emission
power was set 10 W for the mucosal layer and then increased to 16 W for the myotomy.
The total amount of energy delivered and the laser time are summarized in [Table 1]. The two patients with recurrent diverticulum required an energy delivery > 10,000
Joules. The procedure was assisted by a transparent cap in three patients, a flexible
overtube in one, and the Weerda diverticuloscope in one. The postoperative course
was uneventful in all patients and no cervical emphysema or fever were recorded. The
chest film and the gastrographin swallow study on postoperative Day 1 did not show
evidence of pneumomediastinum, leaks or residual pouch ([Fig. 2]). Patients were discharged home within 48 hours on a soft diet. At 1- and 3-month
follow-up visits all patients were satisfied with the procedure and reported improved
swallowing and absence of regurgitation and cough.
Video 1 Thulium-laser assisted cricopharyngeal myotomy.
Table 1
Demographic and operative data
|
Patient
|
Age
|
Sex
|
Septum length (cm)
|
Operative time (min)
|
Energy (J)
|
Laser time (min)
|
Fibers (µm)
|
|
1
|
43
|
F
|
3[1]
|
110
|
10 578
|
21:02
|
272, 365
|
|
2
|
82
|
M
|
2
|
125
|
8012
|
14:05
|
272, 365
|
|
3
|
81
|
F
|
3[1]
|
105
|
11 815
|
19:43
|
272
|
|
4
|
72
|
M
|
2
|
60
|
5408
|
07:51
|
272
|
|
5
|
84
|
F
|
3
|
110
|
8765
|
10:10
|
365
|
1 Recurrent diverticulum
Fig. 2 Gastrographin swallow study before and after flexible endoscopic cricopharyngeal
myotomy.
Discussion
In this pilot study, the Thulium laser beam allowed precise, bloodless incision of
both the mucosal and muscular layers of the septum. Depth of incision was predictable,
with minimal necrosis and lateral thermal spread. The procedure was smokeless and
the fibers of the cricopharyngeal muscle were clearly seen to retract laterally in
all cases, suggesting that microscopic magnification is unnecessary when using Thulium
laser. Neither fever nor cervical emphysema occurred in any of the patients, indicating
that the buccopharyngeal fascia was preserved. Incision time was variable and probably
reflected the learning curve of the procedure. Interestingly, recurrent diverticula
after transoral stapling required more energy delivery, reflecting a greater amount
of tissue fibrosis in the residual septum. Because physical limitations of the stapling
device can explain incomplete division of the cricopharyngeus muscle and clinical
recurrences, especially in diverticula smaller than 3 cm [1], we speculate that the Thulium laser technique may be the preferred initial option
in these patients.
Thulium laser works with a 1.9- to 2.0-μm wavelength with limited lateral thermal
spread (0.1 – 0.3 mm with small fibers), tissue penetration (0.2 – 0.4 mm beyond ablated/cut
tissue layer) and fine coagulation [6]. There have been concerns in the past about creating a perforation at the bottom
of the diverticulum when using the laser technique which is why the results of this
procedure are still considered operator-dependent. According to a cadaveric study
by Chang et al. [8], risk of creating a free mediastinal perforation is significantly reduced by paying
attention to maintaining the integrity of the buccopharyngoesophageal fascia during
the common wall division. It is likely that the buccopharyngeal fascia is displaced
posteriorly by the diverticulum, creating a safer plane to divide the septum without
entering the prevertebral space. However, because the cricopharyngeal muscle represents
only the proximal portion of the common wall, the operator should keep in mind that
the goal of the procedure is, in fact, to perform a cricopharyngeal myotomy and not
to reach the bottom of the pouch. Special care must be taken in patients with recurrent
diverticulum after incomplete transoral stapling due to the possible tissue fibrosis
and asymmetry of the septum.
In the past, CO2 laser treatment for Zenker’s diverticulum has been confined to the domain of otorhinolaryngologists
because of the need of a rigid scope and a special microendoscopic equipment [9]. A recent systematic review and meta-analysis has found that, despite substantial
heterogeneity across studies, flexible endoscopic treatment for Zenker’s diverticulum
with needle knife or IT knife is feasible, safe, and effective [10]. Because the optimal incision technique still remains elusive, it is possible that
in the future, the Thulium laser will be added to the current armamentarium of both
gastroenterologists and surgeons for flexible endoscopic treatment of Zenker diverticulum.
Conclusions
Division of Zenker’s diverticulum septum with Thulium laser appeared feasible and
safe through flexible endoscopy in this pilot study. Experience with a larger patient
cohort with longer follow-up is needed to assess efficacy and effectiveness.
