RECLASSIFYING CONSTIPATION USING COLONIC VOLUME ASSESSED BY MRI, WHOLE GUT TRANSIT, PSYCHOLOGICAL DISTRESS AND PAIN SCORES

Background: The gastrointestinal (GI) disturbance is a frequent complication in patients with thoracolumbar vertebral fracture (TVF), especially in the postoperative period. Laxatives are sometimes of limited effect. Transcutaneous electrical acustimulation (TEA) has been reported to effectively treat functional or secondary constipation and accelerate postoperative gastrointestinal function recovery after abdominal surgery; however, it is unknown whether it has an ameliorating effect on GI disturbances in TVF patients after receiving posterior pedicle screw fixation surgery.
Objectives: This study was designed to investigate the effects of TEA on postoperative recovery and possible mechanisms involving autonomic functions.
Materials and Methods: A total of 81 TVF patients who underwent elective posterior pedicle screw fixation surgery were randomized to receive TEA or sham-TEA. After enrollment, electrocardiogram (ECG) was recorded for 30 min to assess autonomic function. TEA at ST36 or sham-TEA at non-acupoints was performed for one hour twice daily from 24 hours before surgery to postoperative day (POD) 3. Clinical symptoms were assessed in the form of diary. In the morning of POD1 and POD4, the ECG was recorded again for 30 min .
Results: 1) In comparison with sham-TEA, TEA enhanced postoperative recovery associated with lower GI motility (see Fig.1), including a reduction in time to defecation by 27.2% (P =0.002), time to first flatus by 17.2% (P = 0.027), an increase in the Bristol stool score (P = 0.014) and the number of spontaneous bowel movement (SBM,P =0.009). 2) TEA also improved other GI symptoms including abdominal bloating on POD1 and POD4 (P < 0.001 and P=0.001, respectively), straining during defecation (P<0.001) and sensation of anorectal blockage during defecation (P=0.02) in comparison with sham-TEA. 3) TEA reduced the visual analogue scale (VAS) wound pain score on POD1 (P=0.026), POD2 (P< 0.001) and POD3 (P< 0.001). 4) TEA but not sham-TEA increased vagal activity and decreased sympathetic activity (P < 0.001) on POD4 compared with POD1, assessed from the spectral analysis of heart rate variability derived from the ECG. The serum level of norepinephrine (NE) was significantly lower in the TEA group in comparison with the sham-TEA group on both POD1 (P=0.047) and POD4 (P=0.036). 5) The use of TEA was found to be an independent predictor of shortened time to first defecation.
Conclusions: Non-invasive TEA at ST36 is effective in promoting postoperative recovery in TVF patients by enhancing vagal and suppressing sympathetic activities.

Background: Spinal cord injury (SCI) can trigger GI complaints including constipation. The impact of the level of SCI on GI transit and motility needs to be better defined. Furthermore, the natural history of GI dysfunction in patients with SCI is unknown. We performed wireless motility capsule (WMC) studies in patients with SCI: (i) to determine the impact of the level of SCI (cervical [C1-C8] vs. thoracic [T1-T11]) on gastric, small bowel (SB), and colon transit and motility and (ii) to compare GI transit and motility in patients with SCI <10 vs. >10 years duration.
Methods: 25 patients (age 52±14 years, 76% male) with SCI (>1 year) above T12 with chronic constipation underwent WMC testing. Patients on opioids were excluded. Stimulant laxatives and GI motility drugs were stopped 48 hours before testing. Rescue suppository laxatives were permitted at day 7. WMC transit parameters included gastric emptying time (GET)(delayed >5 hours), SB transit time (SBTT)(delayed>6 hours), and colon transit time (CTT)(delayed>59 hours). Motility parameters included contractions per minute and motility index or MI (ln) 30 min prior to WMC pylorus passage (gastric), 30 min after pylorus passage (proximal SB), 30 min before ileocecal junction (ICJ) passage (distal SB), 30 min after ICJ passage (proximal colon), and 30 min before anal expulsion (distal colon).
Results: SCI level was cervical in 17 (68%) and thoracic in 8 (32%) patients; time since SCI was <10 years in 16 (64%) and >10 years in 9 (36%) patients. Transit delays in the stomach, SB, and colon were prevalent and were similar with cervical vs. thoracic SCI (Figure). Transit delays <10 vs. >10 years after SCI were not different for GET (18.8 vs. 44.4%, P=0.35), SBTT (37.5 vs. 44.0%, P=1.00), or CTT (50.0 vs. 33.3%, P=0.66). Proximal SB contraction frequency (P=0.02) and MI (P=0.03) were lower after cervical vs. thoracic SCI, but contraction parameters in other gut regions did not differ in relation to level of injury (Table). Contraction frequencies and MI were similar <10 vs. >10 years across all gut regions (data not shown).
Conclusion: Whole gut transit delays involving the stomach, small bowel, and colon are common after spinal injury. These delays were not secondary to medication effects as opioid use was excluded and drugs with motility actions were discontinued before testing. There was no relation of level of spinal injury to transit delay and minimal impact on small bowel contractility, reinforcing the importance of vigilant attention to bowel regimens in all patients. The stability of GI transit delays and contraction profiles over many years suggests such vigilance may need to be lifelong.

Background: Current classification of patients with constipation into IBS with constipation (IBS-C) and functional constipation (FC) is problematic as symptoms overlap extensively and do not identify distinct mechanisms which might respond to specific therapy . Our primary aim was to determine if we could develop a novel classification of constipation including objective measures of colonic function that predict an individual’s responsivenessto either secretagogues, prokinetics or other therapies. Methods: Healthy volunteers (HVs) and patients with constipation (meeting ROME IV criteria - confirmed by 14-day stool diary) were recruited in London and Nottingham. They completed PAC-SYM and HADS questionnaires at baseline, along with stool diaries documenting stool form (Bristol Stool Form Score - BSFS) and weekly complete spontaneous bowel movements (CSBM). Their pain scores and colonic volume, both baseline and at T=60 and T=120 minutes following dosing with 10ml/kg macrogol (500-1000mL) were assessed using established MRI methods.Transit was measured with a validated MRI marker method and high-resolution manometry performed (see separate abstract). Kmeans clustering using standardised values of the above parameters was used to group the participants with constipation into clusters. Participants with missing data were excluded from this analysis. Results: Table 1 shows the results with patients grouped by the ROME criteria. IBS-C and FC showed significantly larger colon volumes, greater pain and slower transit than HVs with the expected substantial overlap between the 2 patient groups. All patients had hard stools as assessed by BSFS and few CSBMs (Table 1). Cluster analysis of patients suggested an alternative 3-group model based on colon volumes, transit time, maximum pain scores and psychological distress (HADS) (Table 2). Group 1 had large colons, prolonged transit time, hypermotility, high pain and high anxiety scores. Group 2 had a normal colon size but prolonged transit with less pain but similar anxiety. Group 3 by contrast had large colons but faster transit times, overlapping that of HVs, with low pain and low anxiety scores (Table 2). Discussion: Patients labelled as either FC or IBS-C show overlap of both objective and subjective parameters. Our cluster analysis, based on underlying mechanisms, includes measures of both psychological distress and objective colonic function. It identifies a yet unrecognised cluster (Group 3). These individuals have normal transit yet produce hard infrequent stools. We hypothesise that in this group excessive absorption, rather than slow transit, may underly constipation. Such patients may respond better to a secretagogue while those with slow transit (Group 1 & 2) would be predicted to respond to prokinetics. Clinical trials of these contrasting approaches in our 3 clusters are now warranted.