Iatrogenic peripheral nerve injury

Iatrogenic peripheral nerve injury

Treatment

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).

References

1)

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
2)

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. http://www.awmf.org/leitlinien/detail/ll/005-010.html Stand 30.06.2013
6)

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
8)

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
9)

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
10)

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

Vagal Nerve Schwannoma

Vagal Nerve Schwannoma

Epidemiology

Schwannoma arising from the vagus nerve is an uncommon (2–5%) benign nerve tumour.

Vagal Nerve Schwannomas are usually confined to the retrostyloid parapharyngeal space, although patients with schwannomas that extend into the posterior cranial fossa through the jugular foramen have been reported


Schwannomas arising from the vagus nerve are extremely rare in children, with only 16 cases reported in the world literature 1).

Clinical features

They usually presents as an asymptomatic slow growing mass 2).

Most cases of schwannomas manifest between the third and sixth decades of the patient’s life as a slow growing firm, painless mass in the lateral neck. Hoarseness, pain, or cough may be the presenting complaints. They displace the carotid arteries anteriorly and medially, jugular vein laterally and posteriorly. These swellings are mobile transversely but not vertically 3).

Diagnosis

Diagnosis is based on clinical suspicion and confirmation obtained by means of surgical pathology.

Differential diagnosis

Schwannomas of the vagus nerve must be differentiated from the carotid body and glomus vagale tumors because the distinction may influence treatment planning.

Treatment

Surgical excision is the treatment of choice for vagal schwannoma, with recurrence being rare.


Intermittent intraoperative neuromonitoring via selective stimulation of splayed motor fibers running on the schwannoma surface to elicit a compound muscle action potential has been previously reported as a method of preserving vagal motor fibers.

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 4).

Outcome

Nerve damage during surgical resection is associated with significant morbidity 5).

This tumour most often presents as a slow growing asymptomatic solitary neck mass, which rarely undergoes malignant transformation.

Literature review

In a comprehensive literature review on 197 articles reporting 235 cases of cervical vagal schwannomas. Presenting symptoms, treatment approach, and postoperative outcomes were recorded and analyzed.

Vagal schwannomas commonly present as asymptomatic neck masses. When they become symptomatic, surgical resection is the standard of care. Gross total resection is associated with higher postoperative morbidity compared to subtotal resection. Initial reports using intraoperative nerve monitoring have shown improved nerve preservation. Recurrence rates are low.

The combination of intermittent nerve mapping with novel continuous vagal nerve monitoring techniques may reduce postoperative morbidity and could represent the future standard of care for vagal schwannoma treatment 6).

Case series

Case series of three patients who underwent vagal schwannoma excision utilizing a IONM technique. The recurrent laryngeal and vagus nerves were monitored via the laryngeal adductor reflex (LAR) using an electromyographic endotracheal tube.

Three patients with suspected vagal schwannomas were treated surgically using the intracapsular enucleation approach with a combination of intermittent IONM and continuous IONM of the LAR.

This combination of continuous and intermittent IONM can be used to preserve vagal laryngeal innervation and function and may represent the future standard of care for vagal schwannoma excision 7).


Green et al. reported 36 of these rare neoplasms in 35 patients. The majority of the tumors presented as a mass in the upper cervical or parapharyngeal region. Usually the mass was asymptomatic. The following types and frequencies of neoplasms of the vagus nerve were noted: paragangliomas, 50%; neurilemmomas, 31%; neurofibromas, 14%; and neurofibrosarcomas, 6%. Surgical resection, with preservation of the vagus nerve when possible, is the treatment of choice. The clinical features, diagnosis, management, and prognosis of the tumors are presented. Special problems that occur with vagal neoplasms include postoperative dysfunction, catecholamine secretion, and intracranial or skull-base extension 8).

Case reports

In a case report, vagal sensory fibers were mapped and continuously monitored intraoperatively during high vagus schwannoma resection using the laryngeal adductor reflex (LAR). Mapping of nerve fibers on the schwannoma surface enabled identification of sensory fibers. Continuous LAR monitoring during schwannoma subcapsular microsurgical dissection enabled sensory (and motor) vagal fibers to be monitored in real time with excellent postoperative functional outcomes 9).


Keshelava et al. operated one patient for cervical schwannoma causing internal carotid artery (ICA) compression.

The patient underwent en bloc excision via transcervical approach under general anesthesia. Pathological examination demonstrated the diagnosis of schwannoma.

This case shows that VNS can cause ICA compression and therefore brain ischemia 10).


Schwam et al. reported a purely intracranial vagal schwannoma 11).

2018

A 60-year-old female patient was seen at our service for a slow-growing, 9 × 6 cm left-sided cystic neck mass. Preoperative clinical and computed tomography evaluation suggested a diagnosis of a lateral neck cyst. The surgical exploration through the lateral cervicotomy revealed a large cystic mass and clearly identified that the tumor was originating from the left vagal nerve. The histopathologic analysis confirmed the diagnosis of schwannoma. Although uncommon, vagal schwannoma with pronounced cystic component should be included in the differential diagnosis of the cystic neck swellings 12).


A 55-year-old woman who presented to the clinic complaining of throat irritation and feeling of something stuck in her throat for the past three months. On examination, a bulging left parapharyngeal mass was noted, displacing the left tonsil and uvula medially. A contrast-enhanced computed tomography (CT) scan of the neck showed a large, hypervascular soft tissue mass with splaying of the left internal carotid artery. Intraoperatively, the tumor was found to be arising from the vagus nerve. Macroscopic surgical pathology examination showed a tan-red, ovoid, and firm mass. Histopathology showed a benign spindle cell tumor with Antoni A areas with palisading cell nuclei and some degenerative change, confirming the diagnosis of vagus nerve schwannoma. CONCLUSIONS Vagus nerve schwannomas should be distinguished from other tumors that arise in the neck before planning surgery, to minimize the risk of nerve injury. Physicians need to be aware of the differential diagnosis of a neck mass, investigations required, the surgical treatment and the potential postoperative complications 13).


Sreevatsa et al. described three cases of schwannoma involving the vagus who presented differently to our unit during past 5 years 14).


A large vagal neurilemmoma in a 33-year-old man is reported. He complained of slowly progressive palsy of the tongue on the left side. Weakness of soft palate movement was also noted. Magnetic resonance imaging (MRI) revealed a tumour in the left parapharyngeal space with partial extension to the posterior cranial fossa through the jugular foramen. Carotid angiography revealed avascularity of the tumour and anterior shift of the left internal carotid artery. The venous phase showed no blood flow in the internal jugular vein. The tumour was successfully extirpated via a transmandibular transpterygoid approach. Although vagus nerve dysfunction was not observed pre-operatively, the tumour was identified as a neurilemmoma arising from the vagus nerve. The surgical approach should be selected according to the lesion in individual patients. Since neurilemmoma is benign in nature, minimal post-operative sequelae should be expected 15).

References

1)

Mierzwiński J, Wrukowska I, Tyra J, Paczkowski D, Szcześniak T, Haber K. Diagnosis and management of pediatric cervical vagal schwannoma. Int J Pediatr Otorhinolaryngol. 2018 Nov;114:9-14. doi: 10.1016/j.ijporl.2018.08.021. Epub 2018 Aug 23. PubMed PMID: 30262374.
2) , 13)

Ramdass AA, Yao M, Natarajan S, Bakshi PK. A Rare Case of Vagus Nerve Schwannoma Presenting as a Neck Mass. Am J Case Rep. 2017 Aug 21;18:908-911. PubMed PMID: 28824161; PubMed Central PMCID: PMC5574523.
4) , 9)

Sinclair CF, Téllez MJ, Sánchez Roldán MA, Urken M, Ulkatan S. Intraoperative mapping and monitoring of sensory vagal fibers during vagal schwannoma resection. Laryngoscope. 2019 Dec;129(12):E434-E436. doi: 10.1002/lary.28147. Epub 2019 Jun 18. PubMed PMID: 31211430.
5) , 7)

Sandler ML, Sims JR, Sinclair C, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. A novel approach to neurologic function sparing surgical management of vagal schwannomas: Continuous intraoperative nerve monitoring of the laryngeal adductor reflex. Head Neck. 2019 Sep;41(9):E146-E152. doi: 10.1002/hed.25793. Epub 2019 May 6. PubMed PMID: 31058386.
6)

Sandler ML, Sims JR, Sinclair C, Sharif KF, Ho R, Yue LE, Téllez MJ, Ulkatan S, Khorsandi AS, Brandwein-Weber M, Urken ML. Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function. Head Neck. 2019 Jul;41(7):2450-2466. doi: 10.1002/hed.25758. Epub 2019 Apr 7. Review. PubMed PMID: 30957342.
8)

Green JD Jr, Olsen KD, DeSanto LW, Scheithauer BW. Neoplasms of the vagus nerve. Laryngoscope. 1988 Jun;98(6 Pt 1):648-54. PubMed PMID: 2836676.
10)

Keshelava G, Robakidze Z. Cervical Vagal Schwannoma Causing Asymptomatic Internal Carotid Artery Compression. Ann Vasc Surg. 2019 Oct 17. pii: S0890-5096(19)30859-3. doi: 10.1016/j.avsg.2019.09.021. [Epub ahead of print] PubMed PMID: 31629844.
11)

Schwam ZG, Kaul VZ, Shrivastava R, Wanna GB. Purely intracranial vagal schwannoma: A case report of a rare lesion. Am J Otolaryngol. 2019 May – Jun;40(3):443-444. doi: 10.1016/j.amjoto.2019.02.011. Epub 2019 Feb 18. PubMed PMID: 30799212.
12)

Cukic O, Jovanovic MB. Vagus Nerve Schwannoma Mimicking a Lateral Neck Cyst. J Craniofac Surg. 2018 Nov;29(8):e827-e828. doi: 10.1097/SCS.0000000000005006. PubMed PMID: 30320693.
14)

Sreevatsa MR, Srinivasarao RV. Three cases of vagal nerve schwannoma and review of literature. Indian J Otolaryngol Head Neck Surg. 2011 Oct;63(4):310-2. Epub 2011 Apr 8. PubMed PMID: 23024932; PubMed Central PMCID: PMC3227827.
15)

Yumoto E, Nakamura K, Mori T, Yanagihara N. Parapharyngeal vagal neurilemmoma extending to the jugular foramen. J Laryngol Otol. 1996 May;110(5):485-9. PubMed PMID: 8762326.

Plexiform neurofibroma treatment

Plexiform neurofibroma treatment

Since plexiform neurofibromas are a major cause of the burden of disease and may also progress to malignancy, many efforts have been undertaken to find a cure for these tumors. However, neither surgery nor medication has so far produced a breakthrough therapeutic success.

Plexiform neurofibromas with sizable intraspinal extensions and resultant spinal cord compromise pose challenging management problems, because these lesions may involve multiple nerves and engulf adjacent vascular and visceral structures 1).

Decisions about surgical treatment and frequency of follow-up must be made judiciously and individualized for each patient 2).

Plexiform neurofibromas arising in the orbito-temporal area pose a greater challenge due to its critical function and cosmetic importance of the face. Such plexiform neurofibromas, separately designated as orbito-temporal plexiform neurofibromas, show complex symptoms such as severe ptosis, ectropion, lacrimal gland dysfunction, and even vision loss 3).


A clinical phase I study reported significant shrinkage of plexiform neurofibromas following treatment with the MEK inhibitor selumetinib.

Vaassen et al., reported an 11-year-old NF1 patient with a large plexiform neurofibroma of the neck that had led to a sharp-angled kinking of the cervical spine and subsequent myelopathy. Although surgical stabilization of the cervical vertebral column was urgently recommended, the vertebral column was inaccessible due to extensive tumor growth. In this situation, treatment with the MEK inhibitor trametinib was initiated which resulted in a 22% reduction in tumor volume after 6 months of therapy and finally enabled surgery. These data show that MEK inhibitors may not lead to complete disappearance of NF1-associated plexiform neurofibromas but can be an essential step in a multimodal therapeutic approach for these tumors. The course of our patient suggests that MEK inhibitors are likely to play a significant role in providing a cure for one of the most devastating manifestations of NF1 4).

References

1)

Pollack IF, Colak A, Fitz C, Wiener E, Moreland M, Mulvihill JJ. Surgical management of spinal cord compression from plexiform neurofibromas in patients with neurofibromatosis 1. Neurosurgery. 1998 Aug;43(2):248-55; discussion 255-6. PubMed PMID: 9696077.
2)

Gutmann DH, Aylsworth A, Carey JC, Korf B, Marks J, Pyeritz RE, Rubenstein A, Viskochil D. The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA. 1997 Jul 2;278(1):51-7. Review. PubMed PMID: 9207339.
3)

Choi J, Choi HJ, Kang KJ, Kwon H, Shin J. Simultaneous Forehead Lift and Blepharoplasty Techniques in Management of Orbito-Temporal Plexiform Neurofibroma. J Craniofac Surg. 2019 Mar 14. doi: 10.1097/SCS.0000000000005448. [Epub ahead of print] PubMed PMID: 30889063.
4)

Vaassen P, Dürr N, Röhrig A, Willing R, Rosenbaum T. Trametinib Induces Neurofibroma Shrinkage and Enables Surgery. Neuropediatrics. 2019 May 29. doi: 10.1055/s-0039-1691830. [Epub ahead of print] PubMed PMID: 31141829.
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