Neck dissection and OSCC: the challenge of neurological sequelae

Oral Squamous Cell Carcinoma (OSCC) requires rigorous management of lymph node metastases, with neck dissection remaining the cornerstone of surgical treatment. While this intervention is vital for the oncological prognosis, it exposes the patient to neurological risks with severe aesthetic and functional consequences. For the oral and maxillofacial surgeon, nerve preservation is a constant challenge in the face of the requirement for complete resection.

This observational study aimed to precisely evaluate the incidence of neurological complications and their qualitative impacts in 53 patients treated for OSCC. The objective was to correlate the types of neck dissection with the observed deficits, whether motor disorders or sensory disturbances. The authors hypothesize that the anatomical complexity of the neck, coupled with the aggressiveness of certain techniques, generates a morbidity that is undervalued in current practice.

The clinical findings are striking: 60% of patients in this cohort developed postoperative neurological complications. From lip incompetence related to the marginal mandibular nerve to "shoulder syndrome" following accessory nerve damage, the results highlight a high frequency of sequelae. This study thus highlights the need for meticulous surgical technique and systematic sensorimotor follow-up to minimize the impact of these interventions on the patient's life.

Methodology of clinical evaluation

This observational study was conducted within the department of oral and maxillofacial surgery at Dhaka Dental College & Hospital over a period from July 2016 to June 2017. The cohort included 53 patients with histopathologically confirmed oral squamous cell carcinoma (OSCC), who underwent curative neck dissection.

The primary tumor locations identified were the alveolar ridge mucosa (38%), the buccal mucosa (24%), and the retromolar area (24%). The surgical protocols evaluated included radical neck dissection (RND) as well as supraomohyoid neck dissection (SOHND), the latter procedure being the most frequent in 66% of cases.

Postoperative follow-up consisted of a systematic monthly neurological evaluation. The data were subject to a qualitative and quantitative analysis based on two main axes:

• Aesthetic parameters: evaluation of lower lip incompetence and sagging of the labial commissure.
• Functional parameters: measurement of shoulder syndrome (pain, limited arm extension, shoulder drop), lingual deviation, taste disorders (ageusia, hypogeusia) and sensory alterations in the auricular area.

Analysis of post-operative neurological complications

Clinical evaluation shows that 60% of patients who have undergone neck dissection for oral squamous cell carcinoma (OSCC) develop neurological complications. The incidence varies significantly depending on the type of surgical procedure performed.

The impact of the surgical technique is a determining factor in the occurrence of sequelae. The results highlight a direct correlation between the extent of the resection and the neurological risk:

• Radical neck dissection: Presents the highest complication rate, reaching 100% of cases.
• Supraomohyoid neck dissection: Although it is the most frequent procedure (66% of cases), it remains associated with risks of peripheral nerve lesions.

Topographically, the primary tumor sites were mainly located in the alveolar ridge mucosa (38%), followed by the buccal mucosa (24%) and the retromolar region (24%).

Manifestations functional and aesthetic observed

Les complications identifiées se traduisent par des déficits qualitatifs et quantitatifs impactant la qualité de vie des patients. Les observations cliniques rapportent :

• Aesthetic impairments: Lower lip incompetence and drooping of the oral commissure, mainly related to marginal mandibular nerve injury.
• Functional deficits: Shoulder syndrome (pain, limited arm extension, shoulder drop) following damage to the accessory nerve.
• Sensory and special sensory disorders: Tongue deviation, ageusia, hypogeusia and alterations in auricular sensitivity.

Analysis of clinical repercussions

The overall frequency of neurological complications (60%) reported in this study highlights the vulnerability of nerve structures during the surgical management of OSCC. The most frequent involvement concerns the marginal mandibular nerve (24.5%), leading to immediate aesthetic deficits such as lower lip incompetence and drooping of the oral commissure. Spinal accessory nerve involvement (22.6%) constitutes the second major risk, resulting in "shoulder syndrome" characterized by pain and functional limitation of arm extension. These results demonstrate that nerve morbidity remains a major statistical possibility, even with curative intent.

Limits and perspective

Although the study highlights a direct correlation between the extent of the neck dissection and the complication rate (reaching 100% for radical neck dissections), it has limitations. The sample size (n=53) and the follow-up limited to one year do not allow for the evaluation of spontaneous nerve recovery over the long term or the impact of microsurgical preservation techniques. However, the predominance of supraomohyoid neck dissections (66%) in this cohort shows a trend toward selective surgery aimed at reducing morbidity, without, however, eliminating it completely.

Implications for practice

These data confirm that the preservation of sensory and motor functions must be at the heart of surgical planning. The high prevalence of nerve injuries requires the practitioner to perform a systematic monthly post-operative evaluation. A meticulous technique during dissection and the initiation of early rehabilitation are essential to mitigate functional sequelae and preserve the patients' quality of life.

Summary of results

The study reports that 60% of neck dissections result in neurological complications, a figure reaching 100% during radical dissections. The predominant injuries involve the marginal mandibular branch of the facial nerve (24.5%) and the spinal accessory nerve (22.6%), leading to marked aesthetic and functional deficits.

In practical terms, for the practitioner:

• Securing informed consent: Systematically inform the patient of the high statistical risk of labial paresis or shoulder limitation, inherent to OSCC surgery.
• Prioritize selectivity: Favor supraomohyoid neck dissection as soon as the oncological indication permits, in order to reduce the incidence of nerve damage compared to radical techniques.
• Standardizing neurological follow-up: Establish a monthly post-operative sensorimotor evaluation to ensure early detection of signs of neurotmesis or axonotmesis and promptly refer the patient for functional rehabilitation.

Technical lexicon

OSCC (Oral Squamous Cell Carcinoma): Oral squamous cell carcinoma, the most frequent form of oral malignant neoplasia, developing from the squamous epithelium and often requiring cervical lymph node management.

Neck dissection: Surgical procedure for the excision of fibro-fatty and lymphatic structures of the neck, performed for the control of regional metastases.

Marginal mandibular branch of the facial nerve: Motor branch of the facial nerve (VII) running along the lower border of the mandible, responsible for the innervation of the depressor muscles of the lower lip and the labial commissure.

Accessory nerve (spinal nerve): Eleventh pair of cranial nerves (XI) providing motor innervation to the sternocleidomastoid and trapezius muscles; its preservation is a major challenge for the mobility of the shoulder girdle.

Supraomohyoid neck dissection: A variant of selective neck dissection limited to lymph node levels I, II, and III, generally indicated in cases of OSCC without clinically detectable lymphadenopathy (cN0).

Shoulder syndrome: Post-operative functional sequel combining pain, shoulder drop, and limited arm abduction, typically resulting from manipulation or injury of the accessory nerve.

Radical neck dissection: Invasive procedure involving the excision of all cervical lymph node groups (levels I to V), associated with the potential sacrifice of non-lymphatic structures such as nerve XI, the internal jugular vein, and the sternocleidomastoid muscle.

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