Phrenic nerve paralysis and phrenic nerve reconstruction surgery

Quality-of-life impact of diaphragm plication in patients with diaphragmatic paralysis: A retrospective study

OBJECTIVES

While the overall incidence and prevalence of diaphragmatic paralysis are unknown due to a wide variety of underlying causes, symptomatic patients experience a marked decline in their quality of life. The goal of this study was to measure the impact of diaphragm plication surgery on the quality of life in patients who were diagnosed with diaphragmatic paralysis.

METHODS

A retrospective review of the medical records of 46 patients who underwent diaphragmatic plication surgery was performed. The review included patients who experienced unilateral and bilateral diaphragmatic paralysis. Patients who underwent repeat diaphragm plication surgery were also included in the study. Patients from the retrospective cohort were then contacted by telephone to answer the Dyspnea-12 (D-12) questionnaire. Patients were asked to recall the severity of their symptoms and quality of life preplication, 1-month postplication, and 6-month postplication. Severity of symptoms was ranked as either none, mild, moderate, or severe. Values were then assigned to each rank as follows: none = 0, mild = 1, moderate = 2, and severe = 3. Relative change and statistical significance were calculated with preplication measurements used as the baseline. Scores between preplication versus 1-month postplication and 6-month postplication were then compared by Student's paired t-test. All tests were two-sided and statistical significance was set at P < 0.05.

RESULTS

Forty-six patients were included in the study, from which 21 answered the D-12 questionnaire. Average scores from each component of the D-12 questionnaire showed improvement in the severity of symptoms from preplication to 1-month postplication. The latter period was then followed by continued improvement in all areas when symptoms 6-month postplication were assessed.

CONCLUSION

In patients with diaphragmatic paralysis, diaphragm plication was effective in reducing patients' symptoms while improving overall quality of life.

Symptoms Arising From the Diaphragm Muscle: Function and Dysfunction

There can be many reasons that damage the function of the diaphragm, either transiently or permanently, involving one hemilate or both muscle portions. The diaphragm is associated only with breathing, but many other functions are related to it. The patient is not always aware of the presence of diaphragmatic dysfunction, and it is not always immediate to identify non-respiratory diaphragmatic symptoms. Pseudoanginal pain, night sweats, difficulty memorizing, or muscular and visceral problems of the pelvic floor are just some of the disorders linked to reduced diaphragmatic contractility. A decline in respiratory contractile force can be the basis for further pathological conditions that can increase the rate of mortality and morbidity. The article reviews the possible symptoms that may be presented by the patient, which are not necessarily related to lung function.

Electrodiagnostic and ultrasound evaluation of respiratory weakness

Phrenic nerve conduction studies (NCSs) and needle electromyography (EMG) can provide important information on the underlying pathophysiology in patients presenting with unexplained shortness of breath, failure to wean from the ventilator, or consideration of phrenic nerve pacemaker implantation. However, these techniques are often technically challenging, require experience, can lack sensitivity and specificity, and, in the case of diaphragm EMG, involve some degree of risk. Diagnostic high-resolution ultrasound has been introduced in recent years as an adjuvant technique readily available at the bedside that can increase the overall sensitivity and specificity of the neurophysiologic evaluation of respiratory symptoms. Two-dimensional ultrasound in the zone of apposition can identify atrophy and evaluate contractility of the diaphragm, in addition to localizing a safe zone for needle EMG. M-mode ultrasound can identify decreased excursion or paradoxical motion of the diaphragm and can increase the reliability of phrenic NCSs. When used in combination, ultrasound, phrenic NCSs and EMG of the diaphragm can differentiate neuropathic, myopathic, and central disorders, and can offer aid in prognosis that is difficult to arrive at solely from clinical examination. This article will review techniques to successfully perform phrenic NCSs, needle EMG of the diaphragm, and ultrasound of the diaphragm. The discussion will include technical pitfalls and clinical pearls as well as future directions and clinical indications.

The phrenic nerve; the forgotten nerve in head and neck surgery

BACKGROUND

Neck dissection is a commonly performed procedure for oncologic control of head and neck malignancy. With contemporary modified radical and selective neck dissections, haematoma, wound infection, tissue necrosis, chyle leak and injury involving the marginal mandibular, hypoglossal, vagus or accessory nerves are commonly described complications. Although the phrenic nerve courses within the surgical planes explored during a neck dissection and has a vital function in innervating the diaphragm, few studies have been performed to investigate the exact incidence of post-operative phrenic nerve paresis. This study aims to review the literature as to the rate of phrenic nerve injury following neck dissection.

METHODS

A systematic literature review was conducted from 2000 to 2022 including studies reporting on phrenic nerve paresis following neck dissection.

RESULTS

In total, 11 studies were included. The reported rate of immediate post-operative phrenic nerve paresis ranged from 0% to 5.3%, with an average rate of 0.613% (12/1959). The reported rate of phrenic nerve paresis at follow-up (1 month-127 months) ranged from 0% to 4.7%, with an average rate of 1.035% (5/483). There were no cases of bilateral phrenic nerve paresis reported in this period.

CONCLUSIONS

Phrenic nerve paresis is an uncommon complication following neck dissection, often asymptomatic and potentially underreported. Bilateral phrenic nerve paresis is exceedingly rare. Injury can be avoided by staying superficial to the prevertebral fascia when dissecting around the anterior scalene muscle. Routine phrenic nerve integrity monitoring is not commonly utilized but may aid intra-operative phrenic nerve identification or confirmation of function.