DIEP Flap Sensory Recovery Following Direct Neurotization in Breast Reconstruction - A Blinded Prospective Study
Phase: NA
Conditions: Sensitisation
Sponsor: University of Manitoba

 
Protocol v2: DIEP Flap Sensory Recovery Following Direct Neurotization in Breast 
Reconstruction – A Blinded Prospective Study 
 
March 21, 2021 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Protocol v2: DIEP Flap Sensory Recovery Following Direct Neurotization in Breast 
Reconstruction – A Blinded Prospective Study 
 
Research Problem, Background, Hypothesis 
The Deep Inferior Epigastric Perforator (DIEP) flap is the current standard of care in breast 
reconstruction. The DIEP flap does not normally have sensation restored. The presence of 
sensation in a reconstructed breast has been shown to improve patient-rated quality of life 
following mastectomy reconstruction and is an important safety factor for prevention of burns 
and other flap injuries. Unfortunately, women who have breast skin excised during mastectomy 
are reconstructed with a traditional DIEP flap that does not restore sensation to the skin. We 
hypothesize that the breast reconstructed with a DIEP flap and nerve coaptation will have 
improved sensory return compared to the breast reconstructed with a only a DIEP flap (and no 
nerve coaptation). 
  
Study Objective 
We aim to perform a prospective randomized single-blinded trial to evaluate sensory return to 
DIEP flaps following nerve coaptation. 
 
Research Design and Methodology 
• A blinded, prospective study will be performed involving Manitoban women over 18 
years undergoing bilateral breast reconstruction with DIEP flaps. The women will have 
one breast reconstructed in the standard of care (DIEP flap with no nerve coaptation) 
and one breast reconstructed with both DIEP flap and sensory nerve coaptation; the 
side of coaptation will be randomized. Objective sensibility to the breast will be tested 
pre- and post-operatively (3, 6, 12 months) using the Pressure Specified Sensory Device 
(PSSD). Patients will also complete the Breast Q questionnaire postoperatively. 
• The primary inclusion criteria are  
o (1) female subjects older than 18 
o (2) scheduled for immediate bilateral breast reconstruction following bilateral 
non-nipple sparing mastectomy 
o (3) using DIEP free flap reconstruction 
o (4) with a large skin paddle 
• Patients will be excluded if: 
o (1) pre-operative radiation or chemotherapy was performed 
o (2) post-operative radiation or chemotherapy is planned 
o (3) reconstruction is performed in a delayed fashion 
o (4) a nerve conduit is necessary for nerve coaptation 
• Sample size: 30 
• Justification of statistical methods of analyzing results: To have adequate power (80%) 
to detect the MCID of 0.15 using a paired t-test at the alpha = 0.05 level, our required 
sample size ranges from 8 to 23 participants depending on our assumption of a weak or 
strong correlation of 0.2 or 0.8 between the sensation measurements in the left and 
right breast of an individual.  We have also assumed a standard deviation of 0.1912 for a 

single measurement.  To allow for the possibility of dropouts, etc., we therefore 
propose a conservative sample size of 30 participants. 
• Sensory nerve coaptation in the operating room (unilateral): The donor nerve is a 
cutaneous nerve that is identified with the most inferior lateral perforator vessels. The 
nerve is then dissected for neurotization and divided at the level of the fascia where it is 
a pure sensory nerve. The recipient intercostal nerve is usually easily identified in the 
third intercostal space during the dissection of the internal mammary artery and vein. 
The anterior branch of the third intercostal nerve can usually be found at the junction of 
the inferior portion of the third rib and the sternum, approximately 80% of the time. The 
nerve is dissected and transected medially. It is then mobilized to give it the longest 
length possible in preparation for neurotization. Neurotization is performed by coapting 
the donor nerve to the third anterior intercostal nerve directly with a 9-0 nylon suture in 
standard fashion. 
• Blinding: Only the surgeon and principal investigator will know which breast had the 
nerve coaptation performed. Neither the patient nor health care team testing sensory 
recovery to the breast will know. 
 
Definition of adverse and serious adverse events 
Adverse events include neuroma formation at the sensory nerve donor or recipient site. 
However, there are no documented cases in the literature of this occurring during this 
procedure. 
 
Budget Details 
N/A. 
 
Potential Benefits 
The benefit is improved sensation to the reconstructed breast, which increases patient 
satisfaction with the surgery and improves safety and prevention of injury to the breast. 
 
Potential Risks/Harms 
There is a potential for neuroma development at the sensory nerve donor or recipient site. 
However, there are no documented cases in the literature of this occurring in this procedure. 
 
Alternative Treatment 
The alternative treatment is reconstruction of the breast in the standard of care – a DIEP flap 
without nerve coaptation. 
 
Consent Process 
Patients scheduled to receive bilateral breast reconstruction at Health Sciences Centre will be 
screened based on the above inclusion/exclusion criteria. If they qualify for this study, they will 
be contacted and offered enrollment. Prospective patients will be identified during their 
preoperative appointments. A nurse from clinic will seek permission from the potential patient 
to be contacted by research staff. The study protocol and details will be explained by the 
principal investigator or another member of the health care team; a physical copy of this 

information will also be provided to the patients. The principal investigator will review the 
paraphrase and obtain informed consent of the client to participate, unless they are treating 
the participant in which case the co-investigator or another therapy staff member familiar with 
the project and protocol (including all risks and benefits) will review the paraphrase and obtain 
consent. The treating physician will not obtain consent. The potential participants will have 2-4 
weeks to contemplate whether to participate in the study (from preoperative visit to prior to 
surgery).