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The First Smartphone Application for Microsurgery Monitoring: SilpaRamanitor

Kiranantawat, Kidakorn F.R.C.S.T.; Sitpahul, Ngamcherd M.D.; Taeprasartsit, Pinyo; Constantinides, Joannis F.R.C.S.(Plast.)(Ed.); Kruavit, Arthi F.R.C.S.T.; Srimuninnimit, Vichai F.R.C.S.T.; Punyahotra, Narong F.R.C.S.T.; Chatdokmaiprai, Chalermpong F.R.C.S.T.; Numhom, Surawej F.R.C.S.T.

Plastic and Reconstructive Surgery: July 2014 - Volume 134 - Issue 1 - p 130–139
doi: 10.1097/PRS.0000000000000276
Reconstructive: Trunk: Original Articles
Video Discussion

Background: Postoperative monitoring of free flap tissue perfusion is vital. Devices available are expensive and complex to operate. Most surgeons rely on direct clinical observation. A monitoring system that is reliable, inexpensive, and easy to operate is needed. Using mobile phone technology, the authors developed and evaluated a new free flap monitoring system: SilpaRamanitor.

Methods: Software was developed for Android-operated mobile phones. Forty-two normal subjects were recruited to assess its effectiveness. Varying degrees of pressure were applied around the index finger to produce partial venous occlusion, partial arterial occlusion, complete venous occlusion, and complete arterial occlusion sequentially. Photographs of each subject’s index and middle fingers were taken using the smartphone camera. To detect the abnormal perfusion presented on the index finger, the application was instructed to analyze photographs for color difference, with the unoccluded middle finger serving as the control.

Results: The sensitivity, specificity, accuracy, false-negative results, and false-positive results were 94, 98, 95, 6, and 1 percent, respectively. The accuracy of the application in grading occlusion severity was also evaluated. Thirty-nine cases (93 percent) were correctly identified as venous occlusion. The occlusion severity was correctly identified in 33 cases (85 percent). Likewise, for the 40 cases (95 percent) correctly identified as arterial occlusion, the method correctly categorized its severity in 33 cases (83 percent).

Conclusions: The authors developed a new, accurate, and reliable diagnostic system for postoperative microsurgery monitoring using a smartphone application. SilpaRamanitor is inexpensive and easy to use, making it applicable in many microsurgical settings.


Supplemental Digital Content is available in the text.Video Discussion by Ash Patel is available online for this article.

Bangkok, Thailand; and London, United Kingdom

From the Division of Plastic and Maxillofacial Surgery, Department of Surgery, Ramathibodi Hospital, Mahidol University; the Department of Computing, Faculty of Science, Silpakorn University; and the Department of Plastic Surgery, St Thomas’ Hospital.

Received for publication September 12, 2013; accepted February 11, 2014.

Disclosure: The authors have no financial interest in any of the products or devices mentioned in this article.

Supplemental digital content is available for this article. Direct URL citations appear in the text; simply type the URL address into any Web browser to access this content. Clickable links to the material are provided in the HTML text of this article on the Journal’s Web site (

A Video Discussion by Ash Patel accompanies this article. Go to and click on “Video Discussions” in the “Videos” tab to watch.

Kidakorn Kiranantawat, M.D., Division of Plastic and Maxillofacial Surgery, Department of Surgery, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama 6 Road, Rajthevee, Bangkok, Thailand,

©2014American Society of Plastic Surgeons