Keywords
perfusion - hyperspectral imaging - esophageal atresia - anastomotic stricture - anastomotic
leakage
Introduction
Esophageal atresia (EA) with or without tracheoesophageal fistula (TEF) has an incidence
of 1 in 4,099 births.[1] Anastomotic stricture and leakage are frequent problems following repair of EA/TEF,
often due to tension on or compromised perfusion of the anastomosis.[2]
[3] Anastomotic strictures require 5.1 ± 5.6 dilatations on average. Almost all patients
require at least one readmission within the first year of life.[4] The intraoperative assessment of tissue perfusion has recently gained increasing
interest in gastrointestinal surgery.[5] Different methods have been established, the most prevalent being indocyanine green
fluorescence scan.[6]
[7] A drawback of this and other techniques to assess tissue perfusion is the need to
inject contrast agents with potential adverse reactions and toxicity.[8]
Hyperspectral imaging (HSI) is a noninvasive tool for the assessment of tissue perfusion
and oxygenation based on the tissue-specific reflection of light in hyperspectral
ranges of visible and near-infrared light (500–1,000 nm wavelength).[9] It does not require contrast agents and provides near real-time information on tissue
perfusion (near-infrared perfusion index [NIR-PI]), tissue hemoglobin index (THI),
and tissue oxygen saturation (StO2) with 10 to 15 seconds delay.
HSI has been applied to various fields of surgery including cutaneous flaps in reconstructive
surgery, partial nephrectomies, or intestinal anastomoses.[10]
[11]
[12]
[13] We report the first application of HSI in pediatric esophageal surgery.
Case Description
Case 1: A newborn girl (body weight 1,850 g, gestational age 36 weeks) presented with VACTERL
association including EA type C, anorectal malformation with vestibular fistula, and
septum defect. She underwent open TEF repair on day 2 of life. After TEF closure,
the tip of the lower esophagus showed an impaired perfusion on real-time HSI assessment
(NIR-PI 58%; THI 100%; StO2 40%; [Fig. 1A, B]). Thus, an additional 2 mm of the lower esophagus ([Fig. 2]) were resected to accomplish an anastomosis in a well-perfused area (NIR-PI 92%;
THI 100%; StO2 55%; [Fig. 1C, D]). The postoperative course was uneventful. No anastomotic leak or stenosis occurred.
The patient was discharged home on postoperative day 41 due to difficulties related
to her low birth weight and cardiac situation. During the further course of 22 months,
no esophageal dilatations were required.
Fig. 1 Intraoperative situs (A, C) and HSI StO2 (B, D) after TEF ligation: Well-perfused upper esophageal pouch (o) and impaired perfusion of the lower esophagus (#) before resection of its distal tip (A, B). After resection of the tip of the distal pouch (Fig. 2), improved perfusion with
only minor impairment at the anastomotic suture line itself (arrow) was detected (C, D). HSI, hyperspectral imaging; StO2, tissue oxygen saturation; TEF, tracheoesophageal fistula.
Fig. 2 Additional resection of 2 mm distal esophagus after hyperspectral imaging measurement.
Case 2: A 9-month-old boy with EA type A underwent gastric transposition after receiving
a cervical esophagostomy in the newborn period at another institution. After laparotomy,
a good perfusion of the gastric fundus was confirmed and a cervical esophagogastric
anastomosis was established (StO2 80%, THI 100%, NIR-PI 80%; [Fig. 3]). The subsequent course remained uneventful for 26 months. No dilation of the cervical
anastomosis was required. The patient is on full oral feeds.
Fig. 3 Intraoperative situs (A) and HSI assessment (StO2 [B], THI [C], and NIR-PI [D]) before esophagogastric anastomosis for gastric transposition. o, fundus; *, greater curvature; #, antrum; HSI, hyperspectral imaging; NIR-PI, near-infrared perfusion index; StO2, tissue oxygen saturation; THI, tissue hemoglobin index.
Discussion
Anastomotic leakage and stricture after repair of EA/TEF occur in ∼20 and 28% of cases,
respectively.[14] This is, among other factors, caused by an impaired perfusion of the anastomosis.[15] Although intraoperatively the perfusion of the lower esophagus appeared unaltered
macroscopically in patient 1, HSI measurement revealed a diminished perfusion of the
distal pouch. Thus, HSI had an additional diagnostic value. We therefore resected
additional 2 mm of the distal esophagus to create an anastomosis of the two esophageal
ends, which were well perfused. Of note, we recognized an impaired perfusion at the
anastomosis itself, most likely from the suture line ([Fig. 1]), which has been described in adults before.[11]
Currently, several clinical studies are ongoing to evaluate the benefits of HSI in
gastrointestinal anastomoses. A more peripheral adaptation of the anastomosis based
on intraoperative HSI was reported for oncologic esophagectomy in 38% of patients
without any postoperative leak.[16] In another study reporting on colorectal resection, a deviation between the transection
line planned by the surgeon and the border line visualized by HSI of 1 to 13 mm was
found for all patients. Consequently, the resection area was corrected proximally
in 21% of patients due to the intraoperative HSI records. Thus, the authors concluded
that the determination of the resection margin by HSI provide the surgeon with an
objective decision aid for assessment of the best possible perfusion and ideal anastomotic
area in colorectal surgery.[17] Its transferability to other gastrointestinal anastomoses is obvious. However, normal
or cutoff values for different gastrointestinal anastomotic types especially in pediatric
surgery are still required.
Besides HSI, other methods such as indocyanine green fluorescence can also assess
intraoperative perfusion and guide surgeons to improve surgical outcomes.[18] However, this technique requires contrast agents, which is not the case in HSI.
HSI is a safe, fast, noninvasive technique that can easily be implemented during surgery.
The tissue perfusion assessed by HSI is also comparable to that of indocyanine green
fluorescence, which has recently been shown for colorectal resections as well as oncologic
esophagectomy.[16]
[19] HSI has also been shown to discriminate tissue perfusion in acute mesenteric ischemia
and depict tissue viability via reflectance spectra.[20] Besides, it has been applied to evaluate liver and gastric perfusion during pancreatoduodenectomy
and identifying exact resection planes for anatomic liver resection.[21]
[22]
Only recently, also, a HSI system for minimally invasive surgery has been introduced.
The HSI laparoscope available has a diameter of 10 mm and is consistent for object
distances up to 10 cm.[23]
[24] It is currently examined for clinical practicability and impact in adult surgery.
These emerging experiences in adult surgery indicate promising applications in pediatric
surgery. Future tasks include the implementation of HSI measurements in surgical interventions
where adequate tissue perfusion plays a key role. However, to date, there are no reliable
normal and cutoff measurements for decision-making. Moreover, prospective studies
comparing intraoperative perfusion with postoperative outcomes are also lacking. However,
we think that the HSI technique is easy to perform and a promising tool to assess
perfusion in pediatric surgery, which may contribute to better in children.
Conclusion
This is the first report on HSI assessment in pediatric surgery as a safe and noninvasive
tool to assess tissue perfusion in real time. It can help determine the optimal anastomotic
region during pediatric esophageal surgery.
