Lead Researchers:
Professor Ian Cook, Dr Phil Dinning A/Professor David Lubowski, A/Professor Denis King, Ms Linda Hunt
Significance
Constipation is a common cause of suffering that affects 1 in 5 people. While often perceived as a benign, easily treated condition, at least 1/3 of constipated patients presenting to our clinics fail to gain relief from standard therapies such as diet, bulking agents and laxatives. In some cases, patients (who might pass a bowel motion as infrequently as every 2 or 3 weeks) undergo colectomy as a last resort. Unfortunately, this invasive treatment can also yield unsatisfactory results in over 50% of patients so treated. While current Australian figures are not available, in the US the direct and indirect costs of chronic constipation are estimated at US$235 million pa.
Major Achievements
The team at St George Hospital were the first in the world to make prolonged recordings from the human colon in order to describe the contractile mechanisms involved in normal defecation in health. They also discovered that certain types of contractions are deficient in patients with severe debilitating constipation.
Current and Future Research
A technique known as Sacral Nerve Stimulation (SNS) has for some years been used as effective treatment for patients with urinary or faecal incontinence. Patients undergo a simple surgical procedure in which fine wires are placed in close proximity to and stimulate the sacral nerve roots. These wires are connected to a small portable external stimulator implanted under the skin. Researchers at St George Hospital have recently adapted the technique of Sacral Nerve Stimulation to treat severe, refractory constipation. This group was also the first in the world to demonstrate that this technique is a potent stimulus for human colonic propulsive contractions that are deficient in people severely affected by constipation.
Additionally, they were excited to discover that 75% of severely constipated patients experienced normalization of their stool frequency during a 3-week trial period of stimulation. Based on the success of that initial study the team at St George Hospital, secured grant support from NH&MRC Australia and in conjunction with the NH&MRC Clinical Trials Centre, is currently conducting the world’s first randomized controlled trial examining the efficacy of permanent SNS stimulation in treating patients with severe constipation. If successful this study may offer some genuine hope for people suffering this debilitating condition.
Studies are ongoing to elucidate the control of and the complex coordination of contractions within the human colon and how disturbances in such control lead to constipation.
Recent publications
Dinning PG, Bampton PA, Andre J, Kennedy ML, Lubowski DZ, King DW, Cook IJ. Abnormal predefecatory colonic motor patterns define constipation in obstructed defaecation. Gastroenterology 2004; 127:49-58.
Dinning PG, Fuentealba SE, Kennedy ML, Lubowski DZ, King D, Cook IJ. Sacral nerve stimulation induces pan-colonic propagating pressure waves and increases defaecation frequency in patients with slow transit constipation. Colorectal Dis 2007; 9(2): 123-32.
Dinning PG, Szczesniak, M.M. Cook, IJ. Proximal colonic propagating pressure waves sequences and their relationship with movements of content in the proximal human colon. Neurogastroenterol Motility 2008: In Press.
