Recurrent laryngeal nerve palsy

Recurrent laryngeal nerve palsy

Vocal cord paresis, also known as recurrent laryngeal nerve paralysis or vocal fold paralysis, is an injury to one or both recurrent laryngeal nerves (RLNs), which control all muscles of the larynx except for the cricothyroid muscle. The RLN is important for speaking, breathing and swallowing.

Recurrent laryngeal nerve palsy (RLNP) is a potential complication of anterior cervical discectomy and fusion (ACDF).

While performing the anterior cervical approach, injury to important anatomic structures in the vicinity of the dissection represents a serious risk. The midportion of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve are encountered in the anterior approach to the lower cervical spine. The recurrent laryngeal nerve is vulnerable to injury on the right side, especially if ligation of inferior thyroid vessels is performed without paying sufficient attention to the course and position of the nerve, and the external branch of the superior laryngeal nerve is vulnerable to injury during ligature and division of the superior thyroid artery. Avoiding injury to the recurrent laryngeal nerve (especially on the right side) and superior laryngeal nerve is a major consideration in the anterior approach to the lower cervical spine. The sympathetic trunk is situated in close proximity to the medial border of the longus colli muscle at the C6 level (the longus colli diverge laterally, whereas the sympathetic trunk converges medially). The damage leads to the development of Horner’s syndrome with its associated ptosis, meiosis, and anhydrosis. Awareness of the regional anatomy of the sympathetic trunk may help in identifying and preserving this important structure while performing anterior cervical surgery or during exposure of the transverse foramen or uncovertebral joint at the lower cervical levels. Finally, the spinal accessory nerve (embedded in fibroadipose tissue in the posterior triangle of the neck) is prone to injury. Its damage will result in an obvious shoulder droop, loss of shoulder elevation, and pain. Prevention of inadvertant injury to the accessory nerve is critical in the neck dissection 1).

The rate of RLN palsy of 14.1% was greater than any published rate of RLN injury after primary ACDF operations, suggesting that there is a greater risk of hoarseness and dysphagia with reoperative ACDF surgeries than with primary procedures as reported in these studies 2).

The cervical spine is approached from the right side unless the patient has undergone a prior approach from the left side. If so, the original incision line is used. If a patient has subclinical vocal cord palsy on the side of the incision, proceeding with an incision on the opposite side is risky. The potential for recurrent laryngeal nerve palsy is highest on the right side, although the risk has not been documented in recent reports. The thoracic duct, however, can be injured when the approach is from the left side.

For C5–6, the skin incision is made at level of criccoid cartilage, for other levels, appropriate adjustments up or down may be made, sometimes with the assistance of fluoroscopy. The incision is approximately 4–5cm horizontally, centered on the SCM. Many right handed surgeons prefer operating from the right side of the neck, although the risk to the recurrent laryngeal nerve (RLN) is lower with a left sided approach (the RLN lies in a groove between the esophagus and trachea). The skin may be undermined off the platysma to permit a ver- tical incision in the platysma in the same orientation as its muscle fibers. Alternatively, some incise the platysma horizontally with scissors horizontally.

There still is substantial disagreement on the actual prevalence of RLNP after ACDF as well as on risk factors for postoperative RLNP 3).

Case series

The aim of a study of Huschbeck et al. was to describe the prevalence of postoperative RLNP in a cohort of consecutive cases of ACDF and to examine potential risk factors.

This retrospective study included patients who underwent ACDF between 2005 and 2019 at a single neurosurgical center. As part of clinical routine, RLNP was examined prior to and after surgery by independent otorhinolaryngologists using endoscopic laryngoscopy. As potential risk factors for postoperative RLNP, they examined patient’s age, sex, body mass index, multilevel surgery, and the duration of surgery.

214 consecutive cases were included. The prevalence of preoperative RLNP was 1.4% (3/214) and the prevalence of postoperative RLNP was 9% (19/211). The number of operated levels was 1 in 73.5% (155/211), 2 in 24.2% (51/211), and 3 or more in 2.4% (5/211) of cases. Of all cases, 4.7% (10/211) were repeat surgeries. There was no difference in the prevalence of RLNP between the primary surgery group (9.0%, 18/183) versus the repeat surgery group (10.0%, 1/10; p = 0.91). Also, there was no difference in any characteristics between subjects with postoperative RLNP compared with those without postoperative RLNP. We found no association between postoperative RLNP and patient’s age, sex, body mass index, duration of surgery, or number of levels (odds ratios between 0.24 and 1.05; p values between 0.20 and 0.97).

In this cohort, the prevalence of postoperative RLNP after ACDF was 9.0%. The fact that none of the examined variables was associated with the occurrence of RLNP supports the view that postoperative RLNP may depend more on direct mechanical manipulation during surgery than on specific patient or surgical characteristics 4).

A prospective cohort study conducted on 90 patients scheduled for anterior cervical spine surgeries underwent consecutive pre and postoperative vocal cord examination for edema and paralysis by both anterior and lateral approaches laryngeal ultrasonography. Rigid laryngoscopy was the standard confirmatory tool. For postoperative vocal cord edema, the anterior ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 78.9% with PPV = 78.9% and NPV = 88.2% and the novel lateral ultrasonography approach diagnostic sensitivity = 88.2%, specificity = 94.7% with PPV = 93.75% and NPP = 90%. While for paralysis, the anterior ultrasonography approach diagnostic sensitivity = 86.7%, specificity = 85.7% with PPV = 81.25% and NPV = 90% and the novel lateral ultrasonography approach diagnostic (sensitivity, specificity with PPV and NPP) = 100%. The diagnostic accuracy of the novel lateral approach was more correlated to rigid laryngoscopy (91.7% and 100%) compared to anterior approach for vocal cord edema and paralysis (83.3% and 80.6%). Overall incidence of vocal cord paralysis was 16.6%. Risk of vocal cord paralysis was statistically significant more in female, multiple disc herniation, lower and mixed disc levels, Langenbeck retractor, cage and plate and duration of surgery ≥ 1.5 h. Transcutaneous Laryngeal ultrasound is a valid comfortable tool for prediction of vocal cord edema and paralysis after anterior cervical spine surgeries with superiority of the novel lateral over anterior approach 5).

A total of 114 patients undergoing anterior cervical procedures over a 6-year period were included in a retrospective, case-control study. The diagnosis was cervical radiculopathy, and/or myelopathy due to degenerative disc disease, cervical spondylosis, or traumatic cervical spine injury. All our participants underwent surgical treatment, and complications were recorded. The most commonly performed procedure (79%) was anterior cervical discectomy and fusion (ACDF). Fourteen patients (12.3%) underwent anterior cervical corpectomy and interbody fusion, seven (6.1%) ACDF with plating, two (1.7%) odontoid screw fixation, and one anterior removal of osteophytes for severe Forestier’s disease. Mean follow-up time was 42.5 months (range, 6-78 months). The overall complication rate was 13.2%. Specifically, we encountered adjacent intervertebral disc degeneration in 2.7% of our cases, dysphagia in 1.7%, postoperative soft tissue swelling and hematoma in 1.7%, and dural penetration in 1.7%. Additionally, esophageal perforation was observed in 0.9%, aggravation of preexisting myelopathy in 0.9%, symptomatic recurrent laryngeal nerve palsy in 0.9%, mechanical failure in 0.9%, and superficial wound infection in 0.9%. In the vast majority anterior cervical spine surgery-associated complications are minor, requiring no further intervention. Awareness, early recognition, and appropriate management, are of paramount importance for improving the patients’ overall functional outcome 6).

Staartjes et al. analyzed a prospective registry of all consecutive patients undergoing zero-profile ACDF for disc herniation, myelopathy, or stenosis. RLN palsy was defined as persistent patient self-reported dysphagia, hoarseness, or respiratory problems without other identifiable causes. RLN palsy was assessed at scheduled 6-week telephone interviews.

Results: Among 525 included patients, 511 primary and 40 secondary ACDF procedures were performed. Hoarseness was present in 12 (2.2%) cases, whereas dysphagia and respiratory difficulties both occurred in 3 (0.5%) cases. Overall incidence of RLN palsy was 2% after primary procedures and 8% after secondary procedures (P = 0.017). These rates are in line with the peer-reviewed literature, and the difference remained significant after controlling for confounders in a multivariate model (P = 0.033). Other reported risk factors, such as age, sex, surgical time, and multilevel procedures, had no relevant effect (P > 0.05).

Based on our data and other published series in the literature, RLN palsy may occur more frequently after secondary ACDF procedures with a clinically relevant effect size. There is a striking lack of uniformity in methods and reporting in research on RLN injury. 7).



Lu J, Ebraheim NA, Nadim Y, Huntoon M. Anterior approach to the cervical spine: surgical anatomy. Orthopedics. 2000 Aug;23(8):841-5. Review. PubMed PMID: 10952048.

Erwood MS, Hadley MN, Gordon AS, Carroll WR, Agee BS, Walters BC. Recurrent laryngeal nerve injury following reoperative anterior cervical discectomy and fusion: a meta-analysis. J Neurosurg Spine. 2016 Aug;25(2):198-204. doi: 10.3171/2015.9.SPINE15187. Epub 2016 Mar 25. PubMed PMID: 27015129.
3) , 4)

Huschbeck A, Knoop M, Gahleitner A, et al. Recurrent Laryngeal Nerve Palsy after Anterior Cervical Discectomy and Fusion – Prevalence and Risk Factors [published online ahead of print, 2020 Aug 10]. J Neurol Surg A Cent Eur Neurosurg. 2020;10.1055/s-0040-1710351. doi:10.1055/s-0040-1710351

Kamel AAF, Amin OAI, Hassan MAMM, Elmesallamy WAEA, Hassan EM. Ultrasound prediction for vocal cord dysfunction in patients scheduled for anterior cervical spine surgeries: a prospective cohort study [published online ahead of print, 2020 Jun 15]. J Clin Monit Comput. 2020;10.1007/s10877-020-00546-3. doi:10.1007/s10877-020-00546-3

Tasiou A, Giannis T, Brotis AG, Siasios I, Georgiadis I, Gatos H, Tsianaka E, Vagkopoulos K, Paterakis K, Fountas KN. Anterior cervical spine surgery-associated complications in a retrospective case-control study. J Spine Surg. 2017 Sep;3(3):444-459. doi: 10.21037/jss.2017.08.03. Review. PubMed PMID: 29057356; PubMed Central PMCID: PMC5637201.

Staartjes VE, de Wispelaere MP, Schröder ML. Recurrent Laryngeal Nerve Palsy Is More Frequent After Secondary than After Primary Anterior Cervical Discectomy and Fusion: Insights from a Registry of 525 Patients. World Neurosurg. 2018 Aug;116:e1047-e1053. doi: 10.1016/j.wneu.2018.05.162. Epub 2018 Jun 1. PubMed PMID: 29864565

Iatrogenic peripheral nerve injury

Iatrogenic peripheral nerve injury


Iatrogenic peripheral nerve injury is a considerable social and economic concern and the majority of cases are preventable. Complications should be referred to and dealt with promptly by experienced surgeons, to ensure the best chances for optimal functional recovery. Their prevention should be emphasized. Their management should include ensuring early diagnosis, administering an appropriate treatment with rehabilitation, rendering psychological support, and providing control of pain 1).

The combination of morphological assessment (neurosonography) with functional assessment (nerve conduction studies) is of paramount importance in the management of traumatic peripheral nerve injuries. If on sonography, the nerve appears intact, then intraoperative nerve conduction studies the functionality of the nerve. If conduction is impaired (signifying the presence of a neuroma-in-continuity), then nerve grafting is done. If the conduction is somewhat preserved, neurolysis is performed 2).

If it is noted during an operation that a nerve has been severed, it should be repaired immediately during the same operation (primary repair) or within 2–3 weeks (early secondary repair) 3).

The same is true when the nerve is torn or damaged but not cleanly cut. The same operative approach is used as for any other nerve injury. The repair ideally is done with microsurgical tools and magnifying devices, insuring maximal visualization for the repair.

Once again, this ideal situation with the immediate repair is seldom achieved. Usually, the cause of the damage is unknown. In our experience, the operative report rarely provides useful information. When the mechanism for the damage is unknown but there is reason to think that the nerve may regenerate itself, we prefer to wait 3 months with monthly neurological examinations. If at this time, the deficit has not changed or only minimally improved, the nerve should be surgically explored in the next month. If the neurosonographic examination after exposure of the nerve identifies a neuroma, one should not delay. The operation should ideally occur within 3 weeks 4).

A severed nerve should be reconstructed, if possible. Usually, this requires nerve grafting. The sural nerve on the lateral calf is usually used as a source. Other cutaneous nerves such as the saphenous nerve and the medial antebrachial cutaneous nerve can also be used 5). If the nerve appears to be intact, then intraoperative nerve conduction studies help assess how functional it is in the area of damage. If conductivity is impaired, then the affected segment of the nerve surrounded by scar tissue—usually thickened and diagnosed as a neuroma in continuity—is excised and replaced by a transplant. In other cases, when conductivity studies are more promising, it suffices to free the nerve up from the surrounding reactive tissues (neurolysis). In recent years intraoperative neuro sonography has been employed, facilitating the evaluation of individual nerve fascicles, helping distinguish between a complete neuroma in continuity without any residual fascicles and a partial lesion still containing functioning fascicles 6).

The combination of the functional evaluation (nerve conduction studies) and the morphologic assessment (neuro sonography) is very helpful in the surgical management of traumatic injuries in peripheral nerve surgery. The exact approach is documented in the interdisciplinary guidelines of the AWMF “Versorgung peripherer Nervenverletzungen” 7).

A key factor in improving the prognosis is physical therapy, both after the deficit is identified and then post-operatively until re-innervation of the affected muscles has occurred. Electric stimulation therapy is also worthwhile in our option. In this way, the muscle structures can be better maintained until nerve regeneration has occurred.

Case series

Dubuisson et al. analyzed the management of iatrogenic peripheral nerve injury (iNI) in 42 patients.

The iNI occurred mostly during a surgical procedure (n = 39), either on a nerve or plexus (n = 13), on bone, joint, vessel, or soft tissue (n = 24) or because of malpositioning (n = 2). The most commonly injured nerves were the brachial plexusradial nervesciatic nervefemoral nerve, or peroneal nerves. 42.9% of the patients were referred to later than 6 months. A neurological deficit was present in 37 patients and neuropathic pain in 17. Two patients were lost to follow-up. Conservative treatment was applied in 23 patients because of good spontaneous recovery or compensation or because of expected bad prognosis whatever the treatment. Surgical treatment was performed in 17 patients because of known nerve section (n = 2), persistent neurological deficit (n = 12) or invalidating neuropathic pain (n = 3); nerve reconstruction with grafts (n = 8) and neurolysis (n = 8) were the most common procedures. The outcome was satisfactory in 50%. Potential reasons for poor outcomes were a very proximal injury, placement of very long grafts, delayed referral, and predominance of neuropathic pain. According to the literature, delayed referral of iNI for treatment is frequent. They provides an illustrative case of a young girl operated on at 6.5 months for femoral nerve reconstruction with grafts while the nerve section was obvious from the operative note and pathological tissue analysis. Litigation claims (n = 10) resulted in malpractice (n = 2) or therapeutic area (n = 5) (3 unavailable conclusions).

NI can result in considerable disability, pain, and litigation. Optimal management is required 8).

Rasulić et al. describe and analyze iatrogenic nerve injuries in a total of 122 consecutive patients who received surgical treatment at there institution during a period of 10 years, from January 1, 2003, to December 31, 2013. The final outcome evaluation was performed 2 years after surgical treatment.

The most common causes of iatrogenic nerve injuries among patients in the study were the operations of bone fractures (23.9%), lymph node biopsy (19.7%), and carpal tunnel release (18%). The most affected nerves were median nerve (21.3%), accessory nerve (18%), radial nerve (15.6%), and peroneal nerve (11.5%). In 74 (60.7%) patients, surgery was performed 6 months after the injury, and in 48 (39.3%) surgery was performed within 6 months after the injury. In 80 (65.6%) patients, we found lesion in discontinuity, and in 42 (34.4%) patients lesion in continuity. The distribution of surgical procedures performed was as follows: autotransplantation (51.6%), neurolysis (23.8%), nerve transfer (13.9%), direct suture (8.2%), and resection of neuroma (2.5%). In total, we achieved satisfactory recovery in 91 (74.6%), whereas the result was dissatisfactory in 31 (25.4%) patients.

Patients with iatrogenic nerve injuries should be examined as soon as possible by experts with experience in traumatic nerve injuries so that the correct diagnosis can be reached and the appropriate therapy planned. The timing of reconstructive surgery and the technique used are the crucial factors for functional recover 9).

340 patients underwent surgery for iatrogenic nerve injuries over a 23-year period in the District Hospital of Günzburg (Neurosurgical Department of the University of Ulm). In a study published by the authors in 2001, 17.4% of the traumatic nerve lesions treated were iatrogenic. 94% of iatrogenic nerve injuries occurred during surgical procedures 10).



Kumar A, Shukla D, Bhat DI, Devi BI. Iatrogenic peripheral nerve injuries. Neurol India. 2019;67(Supplement):S135-S139. doi:10.4103/0028-3886.250700

Sinha S. Management protocol in the case of iatrogenic peripheral nerve injuries. Neurol India. 2019;67(Supplement):S140-S141. doi:10.4103/0028-3886.250696
3) , 4) , 5) , 7)

Deutsche Gesellschaft für Handchirurgie (DGH), Deutsche Gesellschaft für Neurologie (DGN), Deutsche Gesellschaft für Neurochirurgie (DGNC), Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC), Deutsche Gesellschaft der Plastischen, Rekonstruktiven und Ästhetischen Chirurgen (DGPRÄC), Deutsche Gesellschaft für Unfallchirurgie (DGU) Leitlinen: Versorgung peripherer Nervenverletzungen. Stand 30.06.2013

Koenig RW, Schmidt TE, Heinen CPG, et al. Intraoperative high-resolution ultrasound: a new technique in the management of peripheral nerve disorders. Clinical article Journal of Neurosurgery. 2011;114:514–521

Dubuisson A, Kaschten B, Steinmetz M, et al. Iatrogenic nerve injuries: a potentially serious medical and medicolegal problem. About a series of 42 patients and review of the literature [published online ahead of print, 2020 Jul 11]. Acta Neurol Belg. 2020;10.1007/s13760-020-01424-0. doi:10.1007/s13760-020-01424-0

Rasulić L, Savić A, Vitošević F, et al. Iatrogenic Peripheral Nerve Injuries-Surgical Treatment and Outcome: 10 Years’ Experience. World Neurosurg. 2017;103:841-851.e6. doi:10.1016/j.wneu.2017.04.099

Antoniadis G, Kretschmer T, Pedro MT, König RW, Heinen CP, Richter HP. Iatrogenic nerve injuries: prevalence, diagnosis and treatment. Dtsch Arztebl Int. 2014;111(16):273-279. doi:10.3238/arztebl.2014.0273

Facial nerve schwannoma

Facial nerve schwannoma

Facial nerve schwannoma may arise in any portion of the facial nerve, with a predilection for the geniculate ganglion 1) 2).

They can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare 3).


Even in these tumors, hearing loss tends to precede facial paresis. Hearing loss may be sensorineural from VIII cranial nerve compression from tumors arising in the proximal portion of VII cranial nerve (cisternal or internal auditory canal (IAC) segment), or it may be conductive from erosion of the ossicles by tumors arising in the second (tympanic, or horizontal) segment of VII. Facial palsy (peripheral) may also develop, usually late 4).


Computed tomography (CT) of the temporal bone is important for evaluating the impact on the surrounding structures 5).


Treatment for intracranial facial nerve schwannomas depends on clinical presentation, tumor size, preoperative facial, and hearing function.

Conservative management is recommended for asymptomatic patients with small tumors. Stereotactic radiosurgery may be an option for smaller and symptomatic tumors with good facial function. If tumor is large or the patient has facial paralysis, surgical resection should be indicated. If preservation of the facial nerve is not possible, total resection with nerve grafting should be performed for those patients with facial paralysis, whereas subtotal resection is best for those patients with good facial function 6).

see Middle Fossa Approach for Facial Nerve Schwannoma.

These tumors must be assessed with imaging studies, incisional biopsy is not recommended. The treatment is surgical resection in symptomatic patients with facial paralysis greater than grade III of House-Brackmann, with immediate reconstruction of the nerve 7).

Case series

Facial nerve schwannoma case series.

Case reports

Facial nerve schwannoma case reports.


1) , 4)

Inoue Y, Tabuchi T, Hakuba A, et al. Facial Nerve Neuromas: CT Findings. J Comput Assist Tomogr. 1987; 11:942–947

Tew JM, Yeh HS, Miller GW, Shahbabian S. Intratemporal Schwannoma of the Facial Nerve. Neurosurgery. 1983; 13:186–188

Sade B, Lee JH. Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma. Case report. J Neurosurg. 2007 Jul;107(1):181-4. PubMed PMID: 17639892.

Loos E, Wuyts L, Puls T, Foer B, Casselman JW, Bernaerts A, Vanspauwen R, Offeciers E, Dinther JV, Zarowski A, Somers T. Cochlear Erosion due to a Facial Nerve Schwannoma. J Int Adv Otol. 2019 Jul 9. doi: 10.5152/iao.2019.5304. [Epub ahead of print] PubMed PMID: 31287431.

Xu F, Pan S, Alonso F, Dekker SE, Bambakidis NC. Intracranial Facial Nerve Schwannomas: Current Management and Review of Literature. World Neurosurg. 2017 Apr;100:444-449. doi: 10.1016/j.wneu.2016.09.082. Epub 2016 Sep 28. Review. PubMed PMID: 27693767.

Prado-Calleros HM, Corvera-Behar G, García-de-la-Cruz M, Calderón-Wengerman Ó, Prado A, Pombo-Nava A. Tympanic-mastoid and parotid schwannomas of the facial nerve: clinical presentation related to the anatomic site of origin. Cir Cir. 2019;87(4):377-384. doi: 10.24875/CIRU.18000449. PubMed PMID: 31264987.
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