The Diagnosis and Treatment of a Rare Case of Supraclavicular Neuropathy Following Thoracic Decompression Surgery

The supraclavicular nerve is rarely of clinical significance for many medical providers and even less so for most pain physicians. The following is a case of supraclavicular neuropathy following thoracic outlet decompression to treat Paget–Schroetter syndrome, a venous thrombosis etiology of thoracic outlet syndrome (TOS). A 38-year-old female was referred to our pain management clinic by her vascular surgeon for a new onset of severe right-sided superior chest wall and peri-clavicular pain that began after surgery to address her TOS. She described constant tingling, burning, and numbness which was distinct from the painless swelling and mottling of her right arm prior to her TOS diagnosis. Narcotics and muscle relaxants had provided minimal relief for these new post-operative symptoms. Multiple subsequent ultrasound exams were negative for recurrent venous thrombosis. After 6 weeks of treatment in the pain clinic, which included the initiation of gabapentin, desensitization therapy, repeated local lidocaine injections, and electroacupuncture, she reported 70% improvement in pain. She also endorsed improved functional outcomes, specifically an increased ability to perform overhead activities, wear upper body clothing without severe pain, and improved sleep. This patient represents a rare case of supraclavicular neuropathy following surgery to address a venous etiology of TOS, Paget–Schroetter syndrome. The purpose of this report is to bring awareness of this surgical complication to pain physicians in order to lead to early diagnosis and treatment, and to prevent the development of chronic pain.


Introduction
symptoms. She was treated with therapeutic anticoagulants over the following 3 months and underwent a full hypercoagulable work up with the Hematology Department, which was negative. During the interim period between initial presentation and surgery, she denied any numbness or tingling, pain, swelling, or discoloration in her right upper extremity.
Four months following her initial presentation and diagnosis, she underwent surgical treatment for Paget-Schroetter Syndrome, which included right 1 st rib, anterior scalene, and subclavius muscle resection. This was done with a supraclavicular approach. There were no identified post-operative complications in the chart, and she was discharged 2 days later. The patient herself stated she felt new burning and tingling around her right clavicle immediately following surgery, but it was less severe while she was on a postoperative narcotic regimen. Per protocol, a repeated right upper extremity venogram was performed 2 weeks after surgery, which showed a patent venous system. Subsequent follow-up clinic notes for several months state that the patient reported constant paresthesia, pain, intermittent numbness, and allodynia in the area of her right clavicle and upper chest wall that was not responding to trials of narcotics and muscle relaxants. The patient herself reported an inability to wear sweaters or work shirts due to severe allodynia for months. Three ultrasound assessments of her right upper extremity venous system during this time all showed patent vessels. After minimal improvement with 8 weeks of physical therapy, she was then referred to our pain management clinic.
The initial physical examination revealed a well-healed scar in the right supraclavicular fossa. There was mild, diffuse edema of her right upper extremity and significant allodynia in the right peri-clavicular area associated with patchy numbness to light touch. A neurological exam of her right upper extremity revealed no weakness in any tested muscle groups, symmetric 2+ reflexes, and no other sensory changes distally. Shoulder impingement tests were also negative. A review of systems was negative for feeling lightheaded, shortness of breath, left-sided chest pain, or any recent fevers or chills. She was provided instructions for starting 300mg gabapentin nightly with increasing to twice daily after one week.
She was also instructed on twice-daily desensitization treatment with the aid of 5% lidocaine cream. One week later she returned for a diagnostic supraclavicular nerve block with 5cc 2% lidocaine under ultrasound guidance. Of note, no visible neuroma was seen.
Following this procedure, the patient reported a total resolution of symptoms for 30 minutes with continued 70% relief when seen one week later. She underwent two more supraclavicular nerve blocks over the next two weeks along with two sessions of electroacupuncture. At her follow-up clinic appointment exactly 6 weeks after her initial appointment, she reported overall 70% pain relief and increased function as demonstrated by the ability to sleep throughout the night without pain, wear upper body clothing comfortably, and perform overhead activities. At that time, she was satisfied with her results and deferred further intervention.

Discussion
The supraclavicular nerve and its terminal branches are a rare topic in medical literature in general, and even less so in pain management. Supraclavicular neuropathy or neuralgia has been addressed infrequently in the context of clavicle fracture and surgical treatment thereof. For instance, Labronici et al retrospectively reviewed 255 cases of displaced diaphyseal clavicle fractures in order to report frequency of supraclavicular nerve injury [1]. They The patient presented in this report had a rare form of venous TOS, as the literature generally cites neurogenic TOS as representing 95% of all cases [4][5][6]. There are three approaches to surgical treatment of TOS: a supraclavicular, infraclavicular, and a suprascapular neuropathy has not been mentioned in the literature in the context of TOS and surgical decompression of the thoracic outlet.

Conclusion
We present a very rare case of supraclavicular neuropathy following thoracic outlet decompression surgery. To our knowledge, this potential complication has not been addressed in previous literature. We believe it is important for other pain medicine providers to be aware of this potential complication in order to facilitate prompt diagnosis and treatment, and to prevent the potential development of chronic pain.