Macroglossia in neurosurgery

Abstract Macroglossia, an abnormal swelling of the tongue, is a rare post-operative complication often associated with serious airway obstruction and prolonged intubations. Currently, there is a paucity of information on the true incidence, aetiology, and complications associated with macroglossia. A thorough review of the literature was carried out so as to summarise the characteristics of reported cases of macroglossia and to present potential treatments and preventive strategies. A literature search was conducted in PubMed to identify human case reports of macroglossia after neurosurgical procedures including spine, published in English from 1974 to December 2015. A total of 26 reports with 36 cases of macroglossia were identified. Macroglossia was most commonly reported after sub-occipital and/or posterior fossa craniotomies and spine surgeries in prone or park-bench positions. It is more common after procedures lasting >8 h. The aetiology of macroglossia is multi-factorial and possible mechanisms included local mechanical tongue compression interfering with venous and/or lymphatic drainage, regional venous thrombosis and/or local trauma. Complications included airway obstruction, re-intubation, difficult re-intubation, prolonged intubation and Intensive Care Unit stay and tongue necrosis. Prevention, awareness of the possibility, and early recognition are the best forms of treatment.


INTRODUCTION
Macroglossia, an abnormal swelling of the tongue that may occur in the post-operative period, has been associated with many serious consequences such as acute airway obstruction and prolonged intensive care unit (ICU) admissions [ Figure 1]. The incidence of macroglossia following neurosurgical procedures is not known. Moore et al. reviewed all posterior fossa craniotomies performed at their institution over 6 years and reported an incidence of 1%. [1] However, this potentially serious complication is likely to be more common.

Inclusion criteria
Articles were included if they were case reports that involved macroglossia after neurosurgical procedures in paediatric and adult patients.

Exclusion criteria
Cases were excluded if the surgery was not completed, if swelling also occurred in areas below the neck, if there was a pre-existing congenital macroglossia or if there were multiple surgeries and it was unclear after which surgery the patient developed macroglossia [ Table 1] for the list of case reports included in this review.

Authors Title
Chowhury et al. [8] Macroglossia in a child undergoing posterior fossa surgery in the sitting position Carie et al. [4] Postoperative massive tongue edema in craniosynostotic children Denney [12] Postoperative macroglossia causing airway obstruction Drummond [27] Macroglossia, déjà vu Ellis et al. [3] Massive swelling of the head and neck Hassani et al. [11] A reminder for a very rare entity: Massive tongue swelling after posterior fossa surgery Iwuchukwu et al. [13] Macroglossia associated with brainstem injury Jakobson et al. [32] Life-threatening macroglossia after trauma Kawaguchi et al. [17] Pharyngeal packs can cause massive swelling of the tongue after neurosurgical procedures Koizumi et al. [19] An operation in the park bench position complicated by massive tongue swelling Kuhnert et al. [18] Postoperative macroglossia: Report of a case with rapid resolution after extubation of the trachea Krnacik et al. [6] Severe angioedema causing airway obstruction after anterior cervical surgery Lam et al. [5] Macroglossia: Compartment syndrome of the tongue?
Mayhew et al. [9] Macroglossia in a 16 month-old child after craniotomy Moore et al. [1] Macroglossia and posterior fossa disease McAllister [25] Macroglossia -A positional complication Munshi et al. [30] Postoperative unilateral facial odema: A complication of acute flexion of the neck Miura et al. [7] Massive tongue swelling as a complication after spinal surgery Nimjee et al. [14] Tongue swelling and necrosis after brain tumor surgery Pivalizza et al. [24] Massive macroglossia after posterior fossa surgery in the prone position Sokhal et al. [31] Postoperative lingual edema is not always a predictor of airway compromise Sinha et al. [2] Oropharyngeal swelling and macroglossia after cervical spine surgery in the prone position Tattersall [26] Massive swelling of the face and tongue Teeple et al. [15] Hemimacroglossia and unilateral ischemic necrosis of the tongue in a long-duration neurosurgical procedure Toyama et al. [16] Massive macroglossia developing fast and immediately after endotracheal extubation Tsung et al. [23] Macroglossia after posterior fossa surgery in the prone position -A case report Vermeersch et al. [10] Life threatening macroglossia after posterior fossa surgery: A surgical positioning problem? Journal of Neuroanaesthesiology and Critical Care | Volume 4 • Issue 2 • May-August 2017 |

Data collection
Case reports of macroglossia were reviewed for specific surgical and patient characteristics including: Surgical position, surgical procedure, duration of surgery, timing of the development of macroglossia, location and duration of swelling, any required airway interventions (intubation, tracheostomy, cricothyroidotomy) and the intraoperative use of a bite block, oropharyngeal airway or throat pack. The case reports were also reviewed for patient complications, possible aetiologies, treatments, and recommendations for prevention of macroglossia.

CASE REPORTS
A total of 26 reports with 36 cases of macroglossia (29 following neurosurgery and 7 following spinal surgery) met the inclusion criteria and were reviewed. Eight patients were < age 18. Characteristics of the procedures are shown in Figure 2a-c. Fifty per cent of macroglossia cases occurred in procedures lasting longer than 8 h. The most common surgical positions associated with macroglossia were prone (30.6%), park-bench (25.0%) and sitting (19.4%). The most common procedures associated with macroglossia were sub-occiptal and/or posterior fossa craniotomies (38.9%) and spinal surgery (19.4%). Information about the specific surgical procedure was not available for 13 (36.1%) cases. Duration of macroglossia varied, lasting from 24 h to 12 weeks: <7 days in 6 cases (16.7%), ≥7 days in 18 cases (50.0%), and unknown in 12 cases (33.3%).
The timing to the onset of macroglossia after surgery and required airway interventions for acute airway obstruction (intubation and/or surgical airway) is shown in Table 2. The timing of the onset of macroglossia varied from being present before extubation to >24 h after extubation. Information about timing of macroglossia and required airway interventions was not available for 27.8% of patients. Of the 14 cases of macroglossia present at the end of the surgery before extubation, 8 of these patients were not extubated. There was one additional patient who was not extubated after the surgical procedure for planned mechanical ventilation but later developed macroglossia ≥24 h post-operatively and was subsequently not extubated until post-operative day 12. All other patients included in this review were extubated immediately after surgery. In many patients, re-intubation was reported to be difficult after the development of macroglossia and emergency tracheostomies or cricothyroidotomies were required in some patients. [1][2][3][4][5][6][7] The location of the swelling was pre-dominantly isolated to the tongue in 58.3% (n = 21) of patients. The use of a bite block, oropharyngeal airway and throat pack was reported in 27.8% (n = 10), 5.6% (n = 2) and 16.7% (n = 6) of patients, respectively. One patient had a mouth pack and one patient had gauze packed around the endotracheal tube.

AETIOLOGY
The exact aetiology of macroglossia was difficult to define and the reports listed many possible causes and contributing factors. These are listed in Table 3. However, there are also other considerations in the differential diagnosis of macroglossia. Angioedema may cause macroglossia; but depending on the aetiology, the skin and mucosa of the extremities, bowel, genitalia, face and throat may also be involved. [21] Enlargement of the tongue could be related to infections which could occur acutely from bleeding or odontogenic infections spreading into the floor of the mouth. [22] Excess fluid intake may also be a cofactor for macroglossia; however, the swelling was not be isolated to the tongue. [7] Patients can have pre-existing or chronic macroglossia from conditions such as Beckwith-Wiedemann syndrome, venous and/or lymphatic malformations, focal tumours, amyloidosis, mucopolysaccharidoses and chronic infection. The tongue can be relatively larg if the mandible or maxilla is small, or if there is muscular hypotonia. [22] Different patterns in the development of macroglossia, such as mild and severe, have also been described. [5,23] The mild form is caused by local venous or lymphatic congestion secondary to local compression or venous obstruction. The onset of this macroglossia tends to be immediate. Obstruction of the airway is unlikely because the swelling will be recognised before extubation and the swelling tends to be isolated to the tongue. [23] The severe form is secondary to a re-perfusion injury. The onset may be delayed and may be more dangerous because it can occur after the patient is extubated. In the severe form, areas other than the tongue may be involved. [23] TREATMENT Various considerations for the treatments were r e p o r t e d i n t h e l i t e r a t u r e ; h o w e v e r , t h e i r effectiveness has not been evaluated. In general, patients were placed in the upright position [2,14] to improve venous drainage. The use of medications included oral steroids (dexamethasone, [1,4,9,11,13,18,[23][24][25] hydrocortisone, [23,26] methylprednisolone [10,16,17] and triamcinolone, unspecified [6,7,14,19] ), and topical and oral analgesics. [1] However, steroid treatment was reported to be ineffective in some cases. [9][10][11] Antibiotics and anti-fungal treatments were used when concomitant infection was suspected. [14] Additional medications that were used included: sodium succinate, [10] ranitidine, [10] aerosols (ipratropium bromide, albuterol sulphate), [10] tranexamic acid, [10] promethazine, [10] cetirizine, [10]  Objects placed in the mouth may interfere with venous and lymphatic drainage of the tongue and/or arterial inflow leading to ischaemia (see Figure  3 A, B). Pressure related myonecrosis may also occur.

Regional obstruction
Venous and/or lymphatic obstruction may occur in larger veins draining the head and neck (see Figure 3a and b) Obstruction may occur secondary to positioning (neck flexion or head down position) or external compression Local or regional venous thrombosis May occur locally in the tongue or in larger vessels draining the tongue. A thrombosis may interfere with the venous drainage of the tongue.

Reperfusion injury
Compression of lingual arteries may occur secondary to venous/lymphatic obstruction or from direct compression of the tongue, when obstruction relieved, reperfusion injury may occur. May explain the delayed onset of macroglossia seen in some patients because it does not occur until the venous congestion is relieved to allow arterial inflow.

Dependant oedema
Dependant oedema may occur in the tongue when in the dependant position for a prolonged period of time secondary to the efforts of gravity on venous drainage Neurogenic origin Surgical manipulation of the brain stem, which is thought to be intimately involved with autonomic nervous system supply of the tongue, may lead to abnormal brainstem discharges resulting in macroglossia.

Trauma induced
Trauma may occur secondary to intubation, motor evoked potential monitoring, or from a bite injury from seizures. Journal of Neuroanaesthesiology and Critical Care | Volume 4 • Issue 2 • May-August 2017 | furosemide [4] and phenylephrine. [4] Other treatment modalities included humidified oxygen [1,18] and wrapping the tongue in wet gauze to prevent desiccation. [5,18] Some patients required neck exploration, [5] debridement, [12] and hemi-glossectomy. [17] Glossal massage was reported to hasten the resolution of the lymphatic oedema and stimulate the patient to move their tongue, more which may have contributed, to the resolution of macroglossia. [12] The insertion of single [4,16,18] or bilateral bite blocks [1] after the macroglossia has developed has been suggested to relieve pressure on the tongue.
Many patients required a tracheostomy later in their post-operative course [1,4,5,[8][9][10][11][12][13] to reduce pressure on the tongue from the endotracheal tube. [10] A nasal endotracheal tube may cause less compression on an already swollen tongue and maybe more comfortable for the patient [1] though this has not been shown to be the situation in all patients. [4,18,26] PREVENTION Many recommendations on the prevention of macroglossia were reported. An oral airway (such as Guedel) should not be used because it may cause a tongue compression injury, [2,16,23] especially as most of the pressure from the airway occurs posteriorly in the midline of the tongue and this has a greater effect on the arterial system [ Figure 3a and b]. [12] The use of pharyngeal packs [16] and oral packing [10] should also be avoided unless required because the airway may be contaminated with blood and/or tissue during the surgery. The use of a soft bite block placed between the teeth has been recommended [2,16,24,25,27] as this keeps the mouth in a slightly open position and prevents protrusion of the tongue between the upper and lower teeth. [23] This is important, especially in the lateral, prone, or sitting position, where the tongue may come to rest between the upper and lower teeth. [27] The bite block can move during patient positioning and should be secured to prevent dislodgement and should again be periodically inspected during the case. [28] Although bite blocks are used to prevent injury to the tongue and macroglossia, they can also cause trauma. [29] The position of the bite block should be inspected to ensure that the tongue and the lips are clear of the teeth and not trapped by the bite block. [28] 'Overcrowding' of the mouth leading to tongue compression can easily occur with the use of multiple objects in the mouth -(endotracheal tube, oral gastric tube, temperature probe, oesophageal stethoscope), especially in patients with small mouths or with large tongues. [24] A nasal gastric tube, alternate site for temperature monitoring and precordial stethoscope could be used. [24] A nasal endotracheal tube intraoperatively may decrease the risk of macroglossia and would be less likely to do further damage if swelling developed. [1] If head fixation is with a head holder using a chin bar, the bar that supports the mandible should be checked to ensure that it does not cause soft tissue compression. [2,25] Extreme flexion of the neck should be avoided [2,16] as this may prevent venous drainage and compress the airway, endotracheal tube and tracheal rings against the base of the tongue. [2,23] There should be a distance of a least two finger breadths between the chin and the sternum to avoid this extreme flexion. [23] After positioning, patients should be checked carefully for signs of obstruction (discoloration in the face, lips and tongue). [15,23] The hydration status of the patient should also be carefully monitored as hypervolemic states may produce more swelling. [12] DISCUSSION Macroglossia is an uncommon and rare, but potentially dangerous complication following neurosurgery and spinal surgery. In our review of the literature, we found 36 cases of macroglossia following neurosurgical and spine procedures. Macroglossia has been most commonly reported after subocciptal/posterior fossa craniotomies and spine surgeries and after surgeries in the prone, park-bench and sitting positions. Macroglossia most often occurred after procedures lasting >8 h. The aetiology of macroglossia is likely multi-factorial and varies from case to case. Potential aetiologies include local mechanical compression interfering with venous and/or lymphatic drainage and/or arterial inflow, regional venous and/or lymphatic obstruction, local or regional venous thrombosis, reperfusion injury, neurological origin or trauma associated. Complications included airway obstruction, re-intubation, difficult re-intubation, prolonged intubation and ICU stay and tongue necrosis.
In our review of the literature, there was no standardised approach for the treatment of the patient with acute macroglossia. There was no recommendation about how specifically the airway should be managed in a patient with macroglossia; however, airway management can be challenging and a surgical airway may be needed. Early recognition and more importantly prevention of macroglossia was suggested as the best way to avoid the potentially serious complications of macroglossia. The many different recommendations suggested are summarised in Table 4.

CONCLUSION
Macroglossia following neurosurgical and spine procedures is not common but when it occurs it can be a devastating complication. All patients who are at risk for macroglossia should be carefully examined for any evidence at the end of the procedure. If a patient has any evidence of macroglossia, the safest approach is to leave the patient's trachea intubated until the swelling subsides. Prevention, awareness of the possibility and early recognition are the best forms of treatment.

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Conflicts of interest
There are no conflicts of interest.