Ian Carroll, MD, MS
Clinical Instructor, Anesthesia & Pain Management
PHOTOGRAPH GOES HERE
Curriculum vitae available here.
Stanford Academic Profile available here.
Current Research Studies
Factors causing prolonged post-surgical pain and prolonged opioid use.
Chronic post-surgical pain as a result of nerve injury is a major complication of surgery. In short, virtually every surgery has a definite incidence of chronic neuropathic pain postoperatively. Following elective inguinal hernia repair 24% of patients experience pain 1 year postoperatively. 11% of patients experience moderate to severe pain [2]. Similar numbers exist for other surgeries including: 13% of patients have chronic pain following knee replacement, [3] 6% following cesarean section, [4] 30-60% following thoracotomy [5], and as many as 50% following breast cancer surgery[6].
We are collaborating with the thoracic, breast, general and orthopedic surgery divisions to measure the duration of post surgical pain. We hope to define for the first time a survival curve that describes the natural history of postsurgical pain. By changing our focus from elements influencing pain intensity to those influencing pain duration we hope to gain insight into factors influencing the incidence of delayed pain resolution, and chronic pain. We hope this work will allow us to identify those patients at highest risk of postoperative chronic pain so that they can be targeted in the future for early intervention and treatment. Data collection is currently ongoing in the pilot stage, and this project has provided opportunities for undergraduate students, medical students, and residents to contribute meaningfully in collecting data from patients, and analyzing results. Local collaborators include:
Sean Mackey Pain Medicine
John Pollard Anesthesia
Peter Barelka Pain Medicine/ anesthesia
Stuart Goodman Orthopedic surgery
George Yang General Surgery
Fred Dirbas Breast Surgery
Jessica Donnigton Thoracic Surgery
Richard Whyte Thoracic Surgery
Walter Cannon Thoracic Surgery
This work is exciting because little focus has been given to pain using duration as the primary endpoint. However, it is the chronicity of pain that results on its burden to society, We have excellent means of dealing with pain in the acute setting, but have much worse outcomes in the chronic setting. By focusing on pain duration, we hope to develop new insights into this problem. Ultimately, this research may help to answer the overriding question in pain medicine: Why following identical injuries is pain of short duration for most people but of extended or infinite duration for others?
Brainstem Mechanisms of Analgesia in Patients with Post-Surgical Nerve Pain: an fMRI study.
Only a proportion of patients with neuropathic pain respond to conventional anti-neuropathic pain medications--most of which are sodium channel blockers. The mechanisms responsible for analgesia in response to a sodium channel blocker remain unknown. In this translational research at Stanford Hospital we are using functional MRI to define supraspinal changes in neuropathic pain patients specifically associated with analgesic responses to systemic lidocaine--a prototypical sodium channel blocker. Local Collaborators include:
Sean Mackey Pain Medicine
Funding: Foundation for Anesthesia Education and Research Mentored Research Training Grant.
Dates: January 2007-Present
Botulinum Toxin Sympathectomy for Chronic Sympathetically Maintained Pain. This is a prospective, double blind crossover trial of whether Botox improves duration of analgesia following lumbar sympathetic block. The study is centered at Stanford Hospital. Trial enrollment is nearing completion. Opportunities exist for students and residents to assist in data analysis. Collaborators include:
Sean Mackey Pain Medicine
David Clark Pain Medicine
Dates: January 2005-Present
