Stool dynamics after extrinsic nerve injury during right colectomy with extended D3-mesenterectomy

Two Cases of Refractory Diarrhea Subsequent to Vascular Reconstruction for Infective Superior Mesenteric Artery Aneurysms

Superior mesenteric artery (SMA) aneurysm and their surgical interventions are rare, leading to infrequent reports of postoperative complications. This report describes 2 cases of refractory diarrhea following vascular reconstruction for infectious SMA aneurysms. Both patients underwent aneurysm resection and SMA reconstruction but experienced persistent diarrhea despite treatment with anti-diarrheal medications. Postoperative diarrhea, a complication observed after resection of the nerve plexus around the SMA in gastrointestinal surgery, may be attributed to intraoperative injury to the nerve plexus in our cases. Though palliative therapy is partially effective, more efficacious management strategies are desirable to address this persistent complication.

Reconstructing topography and extent of injury to the superior mesenteric artery plexus in right colectomy with extended D3 mesenterectomy: a composite multimodal 3-dimensional analysis

Background

Superior mesenteric artery plexus (SMAP) injury is reported to cause postoperative intractable diarrhea after pancreatic/colonic surgery with extended lymphadenectomy. This study aims to describe the SMAP microanatomy and extent of injury after right colectomy with extended D3 mesenterectomy for cancer.

Methods

Three groups (I) anatomical dissection, (II) postmortem histology, and (III) surgical specimen histology were included. Nerve count and area were compared between groups II and III and paravascular sheath thickness between groups I and II. 3D models were generated through 3D histology, nanoCT scanning, and finally through 3D printing.

Results

A total of 21 specimens were included as follows: Group (I): 5 (3 females, 80–93 years), the SMAP is a complex mesh surrounding the superior mesenteric artery (SMA), branching out, following peripheral arteries and intertwining between them, (II): 7 (5 females, 71–86 years), nerve count: 53 ± 12.42 (38–68), and area: 1.84 ± 0.50 mm2 (1.16–2.29), and (III): 9 (5 females, 55–69 years), nerve count: 31.6 ± 6.74 (range 23–43), and area: 0.889 ± 0.45 mm2 (range 0.479–1.668). SMAP transection injury is 59% of nerve count and 48% of nerve area at middle colic artery origin level. The median values of paravascular sheath thickness decreased caudally from 2.05 to 1.04 mm (anatomical dissection) and from 2.65 to 1.17 mm (postmortem histology). 3D histology models present nerve fibers exclusively within the paravascular sheath, and lymph nodes were observed only outside. NanoCT-derived models reveal oblique nerve fiber trajectories with inclinations between 35° and 55°. Two 3D-printed models of the SMAP were also achieved in a 1:2 scale.

Conclusion

SMAP surrounds the SMA and branches within the paravascular sheath, while bowel lymph nodes and vessels lie outside. Extent of SMAP injury on histological slides (transection only) was 48% nerve area and 59% nerve count. The 35°–55° inclination range of SMAP nerves possibly imply an even larger injury when plexus excision is performed (lymphadenectomy). Reasons for later improvement of bowel function in these patients can lie in the interarterial nerve fibers between SMA branches.

Long-Term Outcome of Patients with Postoperative Refractory Diarrhea After Tailored Nerve Plexus Dissection Around the Major Visceral Arteries During Pancreatoduodenectomy for Pancreatic Cancer

BACKGROUND

For pancreatic ductal adenocarcinoma (PDAC) surgery, extended dissection of the nerve plexus (pl) around the superior mesenteric artery (SMA) or celiac artery (CA) is sometimes necessary. This consequently results in postoperative refractory diarrhea. This study aimed to evaluate the clinical impact of extended nerve plexus dissection around major arteries on postoperative diarrhea.

METHODS

Patients who underwent pancreatoduodenectomy (PD) for PDAC between January 2013 and December 2016 were included. The frequency of diarrhea (defined as a condition requiring opioid antidiarrheal drug for at least 6 months after surgery) and its short- and long-term outcomes were reviewed.

RESULTS

Of 200 consecutive patients who underwent PD, 78 (39.0%) developed postoperative refractory diarrhea (diarrhea group), and 73 of them (93.6%) underwent hemi-circumferential or more nerve dissection for SMA or CA; both plSMA and plCA dissection were associated with diarrhea. Borderline resectable artery (BR-A) PDAC was included more in the diarrhea group (32.0% vs. 13.1%, P = 0.001); however, the local recurrence rate in the diarrhea group was significantly lower than that in the non-diarrhea group (14.1% vs. 26.2%, P = 0.036). The completion of adjuvant chemotherapy and overall survival were comparable between the two groups. The pre-albumin level improved in 2 years, and 61.3% of patients with diarrhea could stop opioid antidiarrheal drugs within 3 years of surgery.

CONCLUSIONS

Although the frequency of diarrhea increased following nerve plexus dissection around arteries, diarrhea was controllable and resulted in a reduced local recurrence rate. Aggressive dissection of the nerve plexus may be justified for local disease control in BR-A PDAC.