Surgical Treatment of Phrenic Nerve Injury

Unilateral phrenic nerve injury often results in symptomatic hemidiaphragm paralysis. Although diaphragmatic plication is a treatment option, phrenic nerve repair may also be considered in an attempt to restore function of the paralyzed hemidiaphragm and it may be the optimal first line treatment when feasible. Persistently symptomatic patients with phrenic nerve injury and favorable electrodiagnostic testing results may be candidates for phrenic nerve reconstruction. Phrenic nerve reconstruction may involve neurolysis, interposition nerve grafting, and/or neurotization, depending on the extent of the injury.

This video demonstrates surgical repair of the phrenic nerve in a patient diagnosed with right diaphragm paralysis resulting from a prior neck surgery. Intraoperative chest fluoroscopy is performed to confirm the diagnosis and assess for immediate results following phrenic nerve reconstruction. The surgical approach begins with an incision in the area of the supraclavicular fossa. Key landmarks to identify proximity to the phrenic nerve include the posterior border of the sternocleidomastoid muscle medially, the brachial plexus laterally, and the anterior scalene muscle, upon which the phrenic nerve courses. A comprehensive microscopic neurolysis of the phrenic nerve and upper cervical roots is performed.

The sural nerve is then harvested from the leg to be used as an interposition, or bypass, graft. The segment isolated will permit bypass of the injured segment of the phrenic nerve in the neck. Each end of the transected sural nerve is then sewn into a nerve conduit or nerve allograft to promote regeneration and hopefully avoid permanent sequelae of sural nerve sacrifice.

After the phrenic nerve is identified, intraoperative nerve threshold testing is used to evaluate any remaining electrical activity prior to intervention. Careful neurolysis or nerve decompression is performed to dissect away adhesions, sites of vascular compression, and areas of fibrosis along the nerve sheath, in an attempt to restore nerve conductivity. Electrodiagnostic testing is repeated throughout the procedure to objectively assess for immediate improvement.

The sural nerve is then sewn into the phrenic nerve, proximal and distal to the visualized defect. During this bypass, the phrenic nerve is rarely transected. Instead, a small incision is made in the nerve sheath and each end of the nerve graft is sutured in place. A nerve wrap is then applied around both the phrenic nerve proper and the sural nerve interposition graft. This nerve wrap acts to promote regrowth and to prevent recurrence of scar tissue and adhesions. Fibrin glue is also applied as a sealant at the sites of anastomosis.

After closing the incisions and applying the dressings, the patient is partially reversed from anesthesia to the point at which they are breathing spontaneously, so that a postoperative fluoroscopic evaluation may be performed. Partial early recovery can sometimes occur and reveals itself by an increase in lung aeration by one to two rib spaces, suggestive of increased tone in the diaphragm.

Postoperative diaphragm conditioning therapy can likely lead to diaphragm muscle strengthening that will enhance early surgical improvement and lead to further progress. The interposition nerve graft will require several months to regrow and would not be expected to contribute to clinical improvements for up to 10 months.

Suggested Reading

1. Kaufman MR, Bauer TL, Brown DP. Surgical treatment of phrenic nerve injury. In: Friedberg JS, Collins KA, eds. UpToDate. Waltham, MA: UpToDate; 2019. https://www.uptodate.com/contents/surgical-treatment-of-phrenic-nerve-injury. Updated June 27, 2018. Accessed March 18, 2019.
2. Kaufman MR, Elkwood AI, Brown D, et al. Long-term follow-up after phrenic nerve reconstruction for diaphragmatic paralysis: a review of 180 patients [published correction appears in J Reconstr Microsurg. 2017;33(1):e1-e2]. J Reconstr Microsurg. 2017;33(1):63-69.
3. Kaufman M, Bauer T, Massery M, Cece J. Phrenic nerve reconstruction for diaphragmatic paralysis and ventilator dependency. In: Elkwood AI, Kaufman MR, Schneider LF, eds. Rehabilitative Surgery: A Comprehensive Text for an Emerging Field. Cham, Switzerland: Springer; 2017:115-128.
4. Kaufman MR, Elkwood AI, Aboharb F, et al. Diaphragmatic reinnervation in ventilator-dependent patients with cervical spinal cord injury and concomitant phrenic nerve lesions using simultaneous nerve transfers and implantable neurostimulators. J Reconstr Microsurg. 2015;31(5):391-395.
5. Kaufman MR, Elkwood AI, Colicchio AR, et al. Functional restoration of diaphragmatic paralysis: an evaluation of phrenic nerve reconstruction. Ann Thorac Surg. 2014;97(1):260-266.
6. Kaufman MR, Elkwood AI, Rose MI, et al. Surgical treatment of permanent diaphragm paralysis after interscalene nerve block for shoulder surgery. Anesthesiology. 2013;119(2):484-487.
7. Kaufman MR, Willekes LJ, Elkwood AI, et al. Diaphragm paralysis caused by transverse cervical artery compression of the phrenic nerve: the Red Cross syndrome. Clin Neurol Neurosurg. 2012;114(5):502-505.
8. Kaufman MR, Elkwood AI, Rose MI, et al. Reinnervation of the paralyzed diaphragm: application of nerve surgery techniques following unilateral phrenic nerve injury. Chest. 2011;140:191-197.

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