Oral and oropharyngeal cancer remains among the top ten most common malignancies in the United States and worldwide. Over the last several decades the approach to treatment of oral cancer has changed very little with regards to primary tumour extirpation while the approach to the "at risk" lymph nodes has evolved significantly. Perhaps the most significant change in the surgical treatment of cancer is the introduction of free flap for reconstruction post resection. Despite these surgical advances, oral cancer ablation, still results in the sacrifice of several functional and aesthetic organs. The aim of this article was to provide a comprehensive review of the potential long-term complications associated with surgical treatment of oral cancer and their management.
The available English language literature relevant to long-term surgical complications associated with surgical treatment of oral cancer was reviewed. The potential common as well as rarer complications that may be encountered and their treatment are summarized.
In total 50 literature sources were obtained and reviewed. The topics covered in the first part of this review series include ablative surgery complications, issues with speech, swallowing and chewing and neurologic dysfunction.
The early complications associated with oncologic surgery for oral cancer are similar to other surgical procedures. The potential long-term complications however are quite challenging for the oncologic team and the patient who survives oral cancer, primarily due to the highly specialized regional tissues involved in the surgical field.
Oral and oropharyngeal cancer remains among the top ten most common malignancies in
the United States, Europe, and worldwide [
Literature was selected through a search of PubMed, Embase and Cochrane Central Register electronic databases. The keywords used for search were oral cancer, oral surgical procedure, postoperative complications, neurologic dysfunction, speech disorders and swallowing disorders. The search was restricted to English language articles, and books published from March 1962 to June 2010. The included publications were relevant to long-term surgical complications associated with surgical treatment of oral cancer. The potential common as well as rarer complications that may be encountered and their treatment are summarized. The topics covered in the first part of this review series include ablative surgery complications, issues with speech, swallowing and chewing and neurologic dysfunction.
Failure to cure the disease remains the most significant and devastating negative
outcome for the cancer patient and the treating team. Persistent disease, local or
regional recurrence, distant metastasis, or presence of second primary cancer are
among the commonest reasons for failure (
Local failure with extraoral tumour extension.
Local Failure under existing pectoralis major myocutaneous flap.
Regional failure left neck post treatment.
Brain metastasis.
In an attempt to ensure adequate tumour resection, surgeons traditionally submit
frozen tissue sections for examination prior to closure or reconstruction. These
have been proven valuable when found positive for disease, and thus additional
tissue resection is undertaken [
Persistent disease during radiation and chemotherapy.
Surgical resection of cancers in the oral cavity impacts on the two most important
functions of the organs involved: speech and swallowing. More specifically, the oral
preparatory phase (formation of a bolus) and the oral phase of normal deglutition,
can be significantly impaired following tumour ablation. Loss of a significant
portion of the tongue will limit the ability to transfer food into the appropriate
position for grinding by the dentition. Therefore, the first phase of swallowing is
disrupted. The transfer of the bolus from the anterior portion of the oral cavity to
the area of the tonsillar pillars, where the initiation of the swallowing reflex
occurs, constitutes the second phase of swallowing. The harmonious coordination of
the lips, tongue, buccal mucosa and maxillomandibular complex is required for
completion of these phases and progression to the pharyngeal phases of swallowing.
The same structures are associated with speech production and more specifically
articulation. As a general rule, ablative surgery that involves the most anterior
portion of the oral tongue is associated with significantly altered speech, while
resections that incorporate the posterior tongue affect swallowing. As postsurgical
time progresses, surgical site scaring and fibrosis, along with xerostomia from
adjunctive radiotherapy, further impairs speech and swallowing [
Masticatory function is adversely influenced by the surgical management of oral
cancer. The tongue, floor of mouth, maxilla and mandible with the adjacent tissues
are vital structures used for mastication and their anatomic and functional
integrity is altered during ablative surgery. For efficient mastication all three
components of mastication (manipulation, trituration, and consolidation) are
required, and are the result of synchronous interaction of hard and soft tissues
[
Several cranial nerves are at risk during resection of primary tumours as well as neck dissection for removal of "at risk" or involved lymph nodes. Tumour size and location as well as the extent of neck disease if present, often necessitate cranial nerves directly involved or in close proximity to be sacrificed. Furthermore the approaches often required to access and ensure adequate tumour resection can endanger integrity of the cranial nerves in the vicinity (Table 1).
Cranial Nerves at risk for postsurgery dysfunction
1. Spinal accessory nerve |
2. Phrenic nerve |
3. Hypoglossal nerve |
4. Lingual nerve |
5. Vagus nerve |
i) Recurrent laryngeal nerve |
ii) Superior laryngeal nerve |
6. Sympathetic trunk |
7. Marginal mandibular branch of facial nerve |
There are several nerves at risk for iatrogenic injury during extirpative surgery in
the head and neck due to their anatomic proximity to the surgical field, especially
when the surgery involves neck dissection. Nodal metastasis has long been considered
an ominous sign in head and neck cancer, and radical resection of the cervical lymph
nodes, with adjacent muscles, vessels and nerves was advocated. This was based upon
the same principles applied in breast cancer surgery, and it was considered the
primary method of managing this disease process. This type of radical surgery was
accompanied by serious postoperative functional and aesthetic complications.
Shoulder pain and spinal accessory nerve dysfunction are reasons to that have led
surgeons to consider less aggressive surgical techniques to manage cervical nodal
metastasis in the head and neck cancer patient. Nerve preservation is not synonymous
with nerve function preservation, and "shoulder syndrome" can develop even when the
spinal accessory nerve is not sacrificed. Pain, muscle weakness, shoulder movement
restraint, deformity and inability to abduct the upper extremity above 90 degrees
are the results of denervation of the trapezius muscle. Transection of the eleventh
cranial nerve during radical surgery, or excessive manipulation during less radical
procedures, as well as severing the anastomosis with the cervical plexus, may all
result in this complication. Some debate exists in the literature regarding the
actual incidence of developing shoulder syndrome even after preserving the spinal
accessory nerve. All studies have clearly demonstrated that when the nerve trunk and
its anastomosis with the cervical plexus are preserved, patients have better
postoperative function and significantly less pain and deformity. Careful dissection
around the vicinity of the nerve, limited use of electrocautery, and early
identification based on known anatomical landmarks, may help to limit
surgically-induced neural trauma. Direct primary anastomosis of the iatrogenically
severed nerve is possible, and has been described in the literature, however, there
are no available techniques to restore the aesthetic component of "shoulder
syndrome", but aggressive immediate physical therapy can improve functional outcomes
[
The marginal mandibular branch of the facial nerve (C.N. VII) is at risk during
incision and elevation of the flaps for standard neck dissections, and access to the
oral cavity for composite resections. The nerve runs at the under surface of the
platysma muscle and is superficial to the facial vein at the submandibular gland
region. Dingman and Grabb in 1962 [
Dysfunction of right marginal mandibular nerve evident upon animation.
Careful planning of the incisions, taking into consideration the route of the nerve
and identification early during flap elevation, is the best way of preventing
inadvertent iatrogenic injury to this branch of the facial nerve. Some functionality
is normally restored if the neurologic injury is due to traction and not severance
of the nerve, but it may take several months for spontaneous neurosensory recovery
[
Another neurologic complication that may be encountered during neck dissection is
injury to the phrenic nerve. This causes paralysis to the ipsilateral diaphragm
since the phrenic nerve is the only motor innervation to this muscle. The diaphragm
is responsible for 70% of the respiratory movement and long-term pulmonary
complications can originate from this type of injury. An attempt to limit the
surgical dissection to a layer superficial to the pre-vertebral fascia, with
identification of the nerve, may assist surgeons in preventing this complication
[
The hypoglossal nerve (C.N. XII) provides motor innervation to the ipsilateral
tongue, and the lingual nerve (C.N. V3) provides sensation and taste innervation,
via the chorda tympani branch of the facial nerve (C.N. VII), to the anterior 2/3 of
the ipsilateral tongue. Both nerves may be injured iatrogenically during neck
dissection, and excision of the tongue and floor of mouth may further endanger the
lingual nerve. Unless there is gross neural invasion by the cancer, or the path of
the nerve runs directly through the tumour, both nerves are usually preserved.
Hypoglossal nerve dysfunction can present with subclinical symptoms with deviation
of the tongue to the ipsilateral side of injury, accidental tongue biting, and
dysarthria (
Right hypoglossal nerve dysfunction.
Ipsilateral loss of sensation to the tongue from lingual nerve injury can further
impact on the difficulties with mastication, speech, swallowing and injury to the
tongue during speech and mastication. These injuries can occur from traction or
dissection around the lingual nerve during surgery, and may not always be recognized
until later in the postoperative course. A compromised ability to taste foods due to
chorda tympani nerve injury may also contribute to decreased food intake and
malnutrition. Rehabilitation for speech and swallowing, using physical therapy is
usually beneficial for these patients [
Direct or indirect injury to the vagus nerve (C.N. X) or its branches, specifically the recurrent and superior laryngeal nerves, can occur during dissection around the carotid sheath. This is mostly due to the traction on the main trunk of the nerve, or lack of identification of the nerve during neck dissection, or placement of haemostatic clips to control haemorrhage during surgery. Unilateral true vocal cord paralysis, in the median or paramedian position, is the result of injury to the recurrent laryngeal nerve, and is generally well tolerated due to compensation from the intact contralateral vocal cord. However, mild to moderate hoarseness and diminished cough efforts are commonly experienced by patients. This problem becomes even more concerning in cases of bilateral injury when upper airway obstruction may result. Injury to the branches of the superior laryngeal nerve can occur during dissection around the superior thyroid branch of the external carotid artery. This may result in minor swallowing difficulties due to decreased sensation at the laryngeal inlet, or decreased tensor capability of the true vocal cord. Early fatigability and decreased ability to phonate high pitched sounds may seriously affect professional vocalists or public speakers. Direct laryngoscopy alone, or in combination with motor speech evaluation, and a high index of suspicion, can all assist in the accurate diagnosis of these neurologic injuries. Prevention remains the best management, and patients who depend on their voice professionally, require a detailed consultation and evaluation before and after surgery.
Disruption of the sympathetic trunk nerve fibers may cause ipsilateral Horner's
syndrome. This is usually due to a surgical dissection that extends too far medially
behind the carotid sheath. Horner's syndrome involves blepharoptosis due to
disruption of the innervation to Mueller's muscle, miosis or pupillary constriction,
anhidrosis with lack of perspiration of the forehead skin, apparent enophthalmos,
and vascular dilation ipsilateral to the injury. Although the physical findings are
pathognomonic for the diagnosis of Horner's syndrome, the clinical presentation can
be occult and often variable. In addition, since Horner's syndrome findings may be
due to variety of other factors, such as metastasis or vascular injuries, early
recognition is of high importance [
1. The early complications associated with oncologic surgery for oral cancer are the similar to other surgical procedures. The potential long-term complications however are quite challenging for the oncologic team as well as the patient who survives oral cancer, primarily due to the highly specialized regional tissues involved in the surgical field.
2. Some of these complications as evident above can be anticipated mainly due to the nature of the procedures involved for eradication of cancer in the highly specialized head and neck region.
3. It is of paramount importance for the oncology team to discuss possible complications in great detail and appropriately prepare the cancer patent.
4. It is of even greater importance to recognize and avoid those potential complications that would impact the patient's quality of life by strict adherence to basic surgical principles and in depth knowledge of the complex regional anatomy.
The author reports no conflicts of interest related to this study.