The Sir Alan Parks Physiology unit takes its name from the highly regarded surgeon whose name is synonymous with innovation in the field of colon and rectal surgery. Sir Alan Guyatt Parks joined St Mark’s as a consultant surgeon in 1959, where his specialist interest focused on anorectal physiology in relation to continence. His contributions to the field of coloproctology include the study and classification of fistula-in-ano, physiology and anatomy of the pelvic floor.

The physiology unit at St Mark’s offers a specialist approach to the diagnosis and treatment of patients with functional bowel disorders. The multidisciplinary team consists of a consultant surgeon and gastroenterologist, biofeedback nurses, clinical physiologists, technicians, receptionists, secretaries and research fellows.

Each year the unit receives referrals for oesophageal motility disorders and intestinal motility problems such as pseudo-obstruction, IBS, diarrhoea and constipation and faecal incontinence. The latest diagnostic tests are offered and supported by St Mark’s diagnostic services; intestinal imaging and endoscopy procedures. Medical therapy for IBS is offered in conjunction with the unit of psychological medicine; other therapies offered include biofeedback training exercises and surgical treatment.

In addition to patient care the physiology team participate in patient-oriented education, medical education and clinical research.

Consultant surgeon Miss Carolynne Vaizey is Unit Director and has worked in the department since 1995, firstly as a research fellow, then honorary senior research fellow and finally as the surgical consultant.

The physiology unit offers a range of diagnostic studies: stationary oesophageal manometry, ambulatory oesophageal pH and manometry studies, breath hydrogen studies, and studies of pelvic floor function. Active areas of research within the unit include other forms of neuromodulation and exploring new treatments for functional bowel disorder.


Biofeedback is a nurse-led service at St Mark’s; as a behavioural approach it is entirely non-invasive and offers a non-surgical approach as an alternative for patients with bowel dysfunction. The team consists of specialist nurses and physiotherapists who manage patients with a range of functional gastrointestinal disorders; the two largest being faecal incontinence and constipation. Patients can be referred to a gastroenterologist, colorectal surgeon, counsellor, psychologist, psychotherapist, Dietitian and other nurse specialists if required. The biofeedback department has an active body of research on new ways to deliver treatment, including group therapy, transcutaneous nerve stimulation and new irrigation system.