SummaryBreast and/or thoracic pain is a frequent event after breast surgery and is a source of deterioration of patients' quality of life. The development of fibrosis and scar areas around the cutaneous branches of the intercostal nerves is a common cause of pain. Proper clinical investigation associated with the use of ultrasound-guided intercostal nerve cryoablation could be a solution to achieve significant analgesic results.
Key words Post-breast surgery pain syndrome, intercostal nerve cryoablation, nerve entrapment, allodynia, ultrasound guided
RiassuntoIl dolore toracico è un evento frequente dopo chirurgia della mammella ed è fonte di deterioramento della qualità della vita delle pazienti. Lo sviluppo di aree di cicatrice e fibrosi attorno alle branche cutanee dei nervi intercostali è una causa comune di dolore. Una corretta indagine clinica associata con l'uso della crioablazione deinervi intercostali con ultrasuoni potrebbe essere una soluzione per ottenere significativi risultati analgesici.
Parole chiave Sindrome dolorosa dopo chirurgia della mammella, criolesione dei nervi intercostali, intrappolamento nervoso, allodinia
Introduction Breast and/or thoracic painis a frequenteventafter breast surgery. This symptom may develop after many surgical procedures like breast reconstruction after mastectomy, breast remodeling, breast reduction or augmentation and causes a significant deterioration of patients' quality of life1. Intercostal nerve involvement should be considered if surgical complications (infection, seroma, hematoma) or cancer recurrence have been excluded2.
During mastectomy, especially when associated with axillary lymph node dissection, the anterior cutaneous branches of intercostal nerves (T3-T6) are potentially damaged resulting in dysesthetic areas at the lateral, medial and inferior aspect of the breast1.
Materials and methods We report the case of a 42-year-old female patient, BMI 18, who underwent multiple breast surgeries with a subsequent development of a refractory pain syndrome at this level. Past surgical history: double fibroadenoma resection (2012, 2013), breast lipofilling (2013, 2014) and supero-lateral quadrantectomy with sentinel lymph node biopsy for infiltrating lobular carcinoma (pT1a pN0) in May 2015. Adjuvant chemotherapy and radiotherapy were subsequently started. A mastectomy with a prosthetic breast reconstruction was performed in July 2016. Three months after the last intervention she developed an infection with wound dehiscence and partial exposure of the prosthesis at the inferior border of the breast.A new surgical intervention was needed to remove the prosthesis and to perform a latissimus dorsi flap breast reconstruction.
A first pain evaluation was undertaken for poorly controlled pain during the post-operative period. The patient presented left shoulder limited range of motion with analgesic posture and pressure hyperalgesia at left breast area, with pectoralis major trigger point. The latter problem was successfully treated with anaesthetic block with functional limitation disappearance and pain reduction.
A few days later a pain relapse occurred. Two areas of dynamic-mechanical allodynia (striped area in Figure 1) were clearly identified surrounded by an ipo/anaesthetic area to warm, pinprick and touch (dashed area in Figure 1). Furthermore at midaxillary line we observed a positive Tinel sign at the fifth intercostal space with metameric irradiation2.
Therefore we performed an ultrasound guided anaesthetic block of the fifth left intercostal nerve with partial resolution of the pain but with the anterior allodynic area persistence. Ultrasound examination of the area(Figure 2)revealed a fifth intercostal nerve entrapment3at the site where surgical drainage was left in place for a prolonged period (1 month).4-12
Considering the results of the previously performed anaesthetic blocks, after a clinical discussion of the case, the patient was scheduled for a cryoneurolysis of the fifth intercostal nerve that would have been performed one month after the flap breast reconstruction.
Cryoneurolysis procedure One month after the reconstructive surgery, the informed consent was obtained, the patient was conducted to the operating room and positioned in the right lateral decubitus position. The surgical field was prepared with skin disinfection and the patient was draped in a sterile manner.
For the procedure a portable ultrasound machine and probe (Hitachi Aloka ProSound Alpha 6, Medical America, Inc. with high frequency linear ultrasound probe 6-13 MHz) was used.
Due to the reduced thickness of the tissues between skin and the lesion site, the optimal entry point for the nerve lesion was established by ultrasound evaluation at the midaxillary line at the inferior border of the rib. The skin was infiltrated with 1.5 ml of mepivacaine 1% at the entry site. The cryoanalgesia probe (Coo-persurgical 17-gauge trocar 2.5 mm x 1.5 mm tip with 100 mm shaft) was inserted under ultrasound guidance. An in plane technique was used to show the ribs in short axis and the tip of cryoanalgesia probe was positioned at the fifth intercostal space at about 3 mm from the inferior border of the superior rib and 5 mm from the parietal pleura (Figure 3a)(Figure 3b).
Sensory stimulation (50 Hz, 1 ms, 0.5mV) was used to confirm the probe position and the correct perception of paresthesias in the territory of pain. A N2O cryoablation4-11 was done at -78 °C for 2 minutes with 90 seconds pause followed by a second lesion at -78 °C for 2 minutes.
During the lesion, the relationship of the ice ball17 with the surrounding structures was monitored with the ultrasound and the development of a traumatic pneumothorax was excluded (absence of pleural sliding and absence of seashore sign of the pleura under the ice ball).
The procedure was well tolerated and no complication occurred. The patient's pain disappeared within 1 hour after the procedure, the lateral area of dynamic-mechanical allodynia is still absent after 1 month follow-up and the anterior allodynic area is significantly reduced.
Discussion This case demonstrates the importance of ultrasound guidance for the execution of intercostal nerves cryolysis. In skilled hands this technique allows a better control of the procedure by a direct visualization of the distance between the pleura and the needle tip to avoid complications like pneumothorax13-16 and hemothorax. It also represents an excellent opportunity to point out that a correct pain diagnostic-instrumental evaluation and underlying causes consideration are of paramount importance to identify the most appropriate procedure to apply. The persistence of allodynia in the anterior area during anesthesia of the V intercostal nerve let us suppose that the symptom was not only dependent on ectopic pulses multiplication on Aβ fibers at the site of injury/entrapment but also on the persistence of inflammatory reaction at the site of the previous prosthetic infection18,19 (hot area in white in Figure 4); the area is not only innervated by the correspondent intercostal nerve but there is an overlap of fibers from neighboring nerves.4