Pearls and Pitfalls in Oral Cancer Management

Scale
 
0
Able to carry out all normal activities without restriction
1
Restricted in physically strenuous activity, but ambulatory and able to carry out light work
2
Ambulatory and capable of all self-care, but unable to carry out work; up and about more than 50 % of waking hours
3
Capable only of limited self-care; confined to bed more than 50 % of waking hours
4
Completely disabled; cannot carry out any self-care, totally confined to bed or chair
Karnofsky performance scale
100
Normal, no complaints, no evidence of disease
90
Able to carry on normal activity: minor symptoms of disease
80
Normal activity with effort: some symptoms of disease
70
Cares for self: unable to carry on normal activity or active work
60
Requires occasional assistance but is able to care for needs
50
Requires considerable assistance and frequent medical care
40
Disabled: requires special care and assistance
30
Severely disabled: hospitalisation is indicated, death not imminent
20
Very sick, hospitalisation necessary: active treatment necessary
10
Moribund, fatal progressing rapidly
In addition to the above tools, the ACE-27 Index and the ASA risk classification systems have been used to describe comorbidity [3, 4].
The disadvantage of the ACE-27 Index is that it can be time consuming. The ASA stratification though routinely used preoperatively only signifies risk under anesthesia and not as predictor for complications.
Ferrier et al. reviewed 120 patients with head and neck squamous cell carcinoma (HNSCC) and used the ACE-27 and ASA grades to describe comorbidities. They also analysed various other parameters (totally 17 clinical variables) that could be predictors of complications in head and neck surgery. On multivariate analysis duration of anesthesia longer than 360 min, ACE-27 grades and ASA class are reliable predictors of complications and prolonged hospitalization. The authors have however mentioned the need to incorporate the presence of anemia and its correction in any predictor model. This was reflected by its absence in the current ACE-27 [5].
Age itself does not correlate with the incidence of complications. This has been extensively studied in the paper by Boruk et al. [6] This fact has also been corroborated by the study of Myers and Johnson analyzing the effect of advanced age and comorbidities on outcomes in microvascular reconstruction of head and neck defects. Their study showed no significance with advanced chronologic age, though complications were significantly higher in patients with preoperative comorbidities [7].
Determinants of operative risk include:

  1. (a)
    General health status
     
  2. (b)
    Severity of underlying illness
     
  3. (c)
    Nutritional status which can be assessed by weight, body mass index, skin fold measurements, serum albumin and lymphocyte count [8]
     
  4. (d)
    Degree to which surgery will disrupt normal physiologic functions
     
  5. (e)
    Technical complexity of the procedure
     
  6. (f)
    Experience of the treatment team
     
(a) and (b) can be best assessed by the two scales mentioned above.

9.2.2 Evaluation of the Tumor and the Neck and Surgical Planning

  1. 1.
    What is the appropriate modality to image the neck in patients with oral squamous carcinoma?
    For routine evaluation, a contrast-enhanced computed tomographic (CECT) scan which images the primary tumor in the oral cavity, neck and chest is the recommended protocol. A slice thickness of 3–4 mm with spiral scan is preferred.
    In evaluation of the neck, important prognostic indicators are the assessment of tumor necrosis, tumor volume, extranodal spread, involvement of level IV and V, and retropharyngeal lymph nodes. The relation of the mass to the carotid artery is also an important prognosticator indicator with encasement more than 270° suggestive of carotid invasion.
    In salvage and recurrent cases, positron emission tomography-computed tomography (PET-CT) scan along with an ultrasound-guided fine needle aspiration cytology (USGFNAC) can detect metastases greater than 5–6 mm [9].
     
  2. 2.
    Issues with occult metastases and how to avoid pitfalls

    1. (a)
      Computed tomography (CT) scan or Magnetic Resonance Imaging (MRI) has poor sensitivity to detect metastases smaller than 8–9 mm.
       
    2. (b)
      Is USG FNAC an alternate option for the clinically node negative (N0)neck?
      It is an ideal technique for the initial assessment and follow up. However its sensitivity varies from 42 to 73 %. It is operator dependent and requires a skilled sonologist and cytologist.
       
    3. (c)
      If the option of observing the neck is being considered, a strict protocol for follow up and imaging should be adhered to, as regional failure in advanced stages has poorer salvage rates [10, 11].
       
    4. (d)
      What is the role of sentinel lymph node biopsy?
      Currently sentinel node biopsy needs to be considered as an investigational tool and not the standard of care. It may be an alternative option to elective neck dissection in early T1 and T2 oral carcinoma. However it requires expertise in the technique. It does avoid the morbidity of a neck dissection, however a positive node in the sentinel nodal basin has to be converted into an elective neck dissection in a second operation. Intra-operative frozen section of sentinel node is not dependable. It should be used with caution in tumors of the floor of mouth, upper gingiva and palate. Single institutional studies and two multi-institutional trials have reported a pooled estimate of sensitivity of 0.93 and negative predictive values ranging from 0.88 to 1 [1214].
       
     
  3. 3.
    Planning for the neck dissection

    1. (a)
      In a N0 neck, Levels I–III need to be dissected. It is to be extended to Level IV for tongue carcinomas. There is no role for supra-hyoid neck dissection in oral squamous cell carcinoma [1517]
       
    2. (b)
      The predominant nodal basins that need to be addressed based on the patterns of metastasis are Levels I–IV and Vb. The involvement of Level V is less than 5 %. Dissection of this level can be avoided to minimize injury to the spinal accessory nerve due to devascularization and stretch injury.
       
    3. (c)
      Though it is has been proposed that Level IIb dissection can be avoided in N0 neck to minimize injury to accessory nerve; it is to be noted that predominant pattern of neck failure is at Level II in oral cavity cancer. For complete clearance of Level IIa group of nodes, it may be necessary to dissect Level IIb.
       
    4. (d)
      The use of a single transverse neck crease incision affords accessibility to all neck nodal levels [18].
       
    5. (e)
      When performing bilateral neck dissections, address the neck with the lesser tumor burden first trying to preserve the ipsilateral internal jugular vein (IJV), in case the contralateral IJV needs to be sacrificed. Consider reconstruction of the IJV or a staging of the neck dissection if the need to sacrifice both IJV arises. Complications specific to the sacrifice of the IJV are extensive facial and neck edema, raised intracranial pressure, blindness due to intra-cranial hypertension or ischemic optic neuropathy [19].
       
     

9.3 Surgical Complications

9.3.1 General

  1. 1.
    Management of the airway
    Evaluation and management of the airway is of utmost importance in oral cancer surgery, as patients with resection of tumors of the oral cavity especially involving part of the base of tongue hinders the oral phase of swallowing resulting in increased chances of aspiration. Secondly, postoperative edema and a bulky flap can result in compromise of the airway. Finally, in case the patient needs re-exploration under general anesthesia, airway access may become difficult due to compromised mouth opening and distortion of the anatomy of the oral cavity following the initial surgery.
    What would be the mandatory indications for a tracheostomy in oral cavity tumor resections?

    1. 1.
      Extensive tongue resection especially including part of base of tongue and anterior tongue with the arch of the mandible (Fig. 9.1a)

      A325459_1_En_9_Fig1_HTML.jpg
      Fig. 9.1

      (a) Total glossectomy defect that necessitates tracheostomy. (b) Initial bulk of the flap used to obliterate the infratemporal fossa and maxilla necessitating tracheostomy. (c) Intraoral view showing the bulk of the flap with restricted tongue mobility. (d) Bulk of the flap that restricts ability to expectorate secretions and also more prone to secretions from the nasopharynx necessitating a tracheostomy
       
    2. 2.
      Bulky flap reconstruction with obliteration of the infratemporal fossa and nasopharynx and sinuses. There is an increased chance of silent aspiration due to secretions from the nasopharynx (Fig. 9.1b–d)
       
    3. 3.
      Compromised mouth opening
       
    4. 4.
      Perceived need for re-exploration
       
     
  2. 2.
    Non-functioning surgical drains
    Suction drains commonly employed during surgery can malfunction due to air-leak. This can lead to major complications such as accumulation of hematoma causing compression of flap pedicle and neck flaps not adhering to the surgical bed causing delay in wound healing. Air leaks in the suction drain can occur due to a number of causes.

    1. 1.
      Inadequate skin closure technique
       
    2. 2.
      Inappropriate placement and fixation of the drain
       
    3. 3.
      Lack of water-tight mucosal closure
       
    4. 4.
      Neck wound communicating with the tracheostomy site
      Air leaks usually become evident either immediately after surgery during reversal of anesthesia or in the first postoperative day when the patient starts moving his neck. Leaks due to inappropriate skin closure or faulty drain placement can be easily managed by the bedside. However, mucosal leaks and neck wounds communicating with the tracheostomy site can be a serious complication owing to the contaminated oral and tracheal secretions draining into the neck which may lead to vascular blow outs. Thus early identification and closure of the site of leak is desirable which may require re-exploration of the surgical wound in the operating room.
       
     

9.3.2 Complications Arising During Neck Dissection

  1. 1.
    Chyle fistula
    The thoracic duct is an endothelial lined vascular structure transporting chylous material into the inferior portion of the internal jugular vein. Although named as a single structure, it is in fact an arborized series of chylous vessels intermingling with the lymphatic vessels. Mostly encountered in the left side, similar structure can also be seen on the right side along with the level IV lymphatics.
    Chyle leak can occur while carrying out neck dissections at level IV region. In a review of 823 neck dissections (which included level IV nodal clearance), Spiro and Strong reported 1.9 % incidence of chyle leak [20]. This and other studies found that most patients developing postoperative chylous fistula had the leak identified and repaired intraoperatively. This fact highlights the importance of meticulous intra-operative assessment and management of chyle leak [21].
    How to prevent and manage a chyle leak intra operatively

    1. 1.
      Meticulous surgical dissection at level IV region preferably under loupe magnification.
      The lymphatics in the medial aspect of level IV nodal basin overlying the phrenic nerve and extending even more medially to the posterior aspect of carotid sheath is the area where chyle duct (s) are mostly encountered. Dissection from lateral to medial direction with ligation of all fatty and lymphatic structures should be undertaken to prevent a leak.
       
    2. 2.
      At the end of the surgery, the area should be inspected during Valsalva manoeuvre with head end of the table lowered. This should be done for about 20–30 s and any suspected leak should be identified and ligated.
       
    3. 3.
      A non-absorbable suture material should be used to ligate the chyle duct. Reliable ligation of the fine chyle duct may not be always possible; transfixation with the aid of a piece of free skeletal muscle graft to the surgical bed is advised.
       
    4. 4.
      No suction drain should be placed in direct contact with the chylous vessel. A small piece of gelfoam may be placed over the area for additional protection.
       
    5. 5.
      Finally, the right side of the root of neck should also be inspected before closure
       
    Management of postoperative chyle leak
    Chyle leak detected postoperatively is managed as per the daily output. Conservative treatment is preferred when the daily output is less than 600 ml. It includes

    1. 1.
      Head elevation
       
    2. 2.
      Continuous suction drain
       
    3. 3.
      Pressure dressing
       
    4. 4.
      Maintenance of nutrition
       
    This is achieved by an enteral diet rich in medium chain fatty acids or total parenteral diet. The rationale for the former is that long chain fatty acids are broken down into fatty acids and glycerol. The fatty acids are packed in chylomicrons and absorbed into lymphatic ducts. Medium chain fatty acids, on the other hand, are absorbed in the portal system directly bypassing the lymphatics. Martin et al. showed that the use of enteral medium chain fatty acids are effective in the management of postoperative chyle fistula and prevented the need for parenteral nutrition [22].
    Surgical management is reserved for daily output more than 600 ml. Early surgery is warranted as the tissues surrounding the site of leak will get inflamed on exposure to chyle and resuturing will get more difficult with passage of time. Various agents have been used locally which includes fibrin glue, sclerosants like tetracycline and doxycycline and muscle transposition flaps [23]. If there is failure to obtain complete seal of chyle leak, thoracoscopic ligation of thoracic duct is an alternative.
     
  2. 2.
    Nerve injury
    Although multiple nerves encountered in oral cavity and neck surgery, those at risk of injury are the marginal mandibular branch of facial nerve and the spinal accessory nerve.
    The marginal mandibular nerve (MMN) supplies motor fibers to the depressorangulioris and the depressor labii inferioris. Injury to this nerve results in sagging of the ipsilateral lip giving a bad cosmetic outcome. At times however, division of the platysma results in pseudoparalysis of the MMN which usually recovers spontaneously [24].
    Relevant anatomy
    At the region of the facial artery crossing the mandible, the nerve lies above the inferior border of the mandible, in 81 % lateral to the vessels. It dips 1 cm or less below the inferior border of the mandible in 19 % of the patients [25]. Anterior to the facial artery, all branches of the MMN lie above the inferior border of the mandible. However in elderly patients, due to ptosis of the submandibular gland, the nerve may lie 3–4 cms below the lower border of the mandible [26].
    Following neck dissection involving level I, the reported incidence of neuropraxia is 29 % and persistent paralysis 16 % [27]. Neuropraxia usually resolves in 3–6 months.
    Prevention of nerve injury

    1. 1.
      Neck incision
      The neck incision should be made 3 cms below lower border of the mandible along a neck crease.
      The neck flap should be elevated in a plane immediately medial to the platysma (subplatysmal plane) and submandibular gland capsule.
       
    2. 2.
      “Indirect technique” of preservation of the nerve:
      As the submandibular gland is approached, the superficial layer of the deep cervical fascia is incised and elevated with the neck flap. As the MMN lies above the fascia, it gets retracted along with the fascia preventing its injury. Although this is a safe technique of preserving the nerve, metastatic prefacial nodes may be missed and separate dissection and removal of these nodes need to be performed, which will be along the facial vessels and close proximity to the MMN.
       
    3. 3.
      “Direct technique” of preservation of the nerve
      The skin flap is elevated in the subplatysmal plane upto the lower border of the mandible. The nerve is dissected immediately below the lower border of the mandible for about 2–3 cms upto the crossing with the facial artery. Suspicious prefacial nodes are dissected free of the nerve and removed. Level IB nodal clearance is done with the nerve under direct vision.
      Although the “direct technique” has more chances of neurapraxia, it is oncologically safer in patients having a high risk of metastatic pre facial nodes.
       
    The spinal accessory nerve (SAN) exits the anterior wall of jugular foramen and courses medially to enter the upper third of the sternocleidomastoid muscle. The nerve crosses the internal jugular vein at the skull base either superficial (70 %) or deep (30 %) to the vein. The SAN gives off muscular branches to the sternocleidomastoid muscle and enters the posterior triangle of the neck 1 cm above the Erb’s point [28]. It traverses the posterior triangle in the sub-fascial plane and enters the deep surface of the trapezius 2–5 cms above the clavicle.
    The nerve is most prone to damage during level IIB and V nodal clearance. (Fig. 9.2)

    A325459_1_En_9_Fig2_HTML.jpg
    Fig. 9.2

    Patient showing the delayed sequelae of spinal accessory nerve paresis with restricted abduction at the left shoulder and the drooping
    Prevention of nerve injury

    1. 1.
      As the nerve traverses the posterior triangle, care should be taken during elevation of the neck flap. The nerve is more superficial than assumed.
       
    2. 2.
      The nerve is identified 1 cm superior to the Erb’s point and traced as it enters the deep surface of the trapezius. There can be multiple terminal branches of the nerve which need to be preserved.
       
    3. 3.
      There may be contributions from cervical nerves. With gentle traction of the nerve at the posterior triangle, the cervical nerve roots can be identified and preserved.
       
    4. 4.
      During dissection of level II nodes, dissection should be done between the sternocleidomastoid muscle (SCM) and enveloping deep cervical fascia. The nerve is seen entering the muscle approximately at the junction of upper 1/3rd and lower 2/3rd. The nerve is dissected either anterograde or retrograde from the posterior belly of digastric to the entry point in SCM. With gentle traction on the nerve using a vessel loop or a nerve hook, level IIB nodes are cleared.
       
    5. 5.
      Electrocautery is best avoided near the nerve
       
    6. 6.
      If a segment of the nerve is sacrificed due to oncologic reasons, it may be reconstructed using the sural or the greater auricular nerve after confirming no perineural spread (by frozen section) along the preserved segments of the nerve.
       
     
  3. 3.
    Vascular complications
    Major vascular blow out is a culmination of several complications.

    1. 1.
      Salivary fistula resulting in saliva trickling into neck wound is the major cause.
       
    2. 2.
      Improperly planned skin incisions especially in postradiated patients resulting in wound break down and exposure of the vessels.
       
    3. 3.
      Sub-adventitial dissection of the carotids resulting in deprivation of the vessels of the vasovasorum
       
    Carotid blow out is a lethal complication with a mortality of spontaneous rupture being as high as 50 % [29].
    Prevention and management

    1. 1.
      In established oro-cutaneous fistula, the neck wound should be explored and divert the salivary flow away from the great vessels. SCM muscle or scalene muscles may be used to protect the carotid artery.
       
    2. 2.
      In case of exposed vessels due to skin wound breakdown, the vessels should be covered with moist dressing and all slough should be debrided.
       
    3. 3.
      Carotid rupture is mostly preceded by a “sentinel bleed”. This should receive prompt attention and elective ligation. Endovascular stenting is an alternative for impending rupture. Pre-emptive stenting of the internal carotid artery and detachable balloon occlusion of external carotid artery may be carried out. It is necessary to cover the exposed carotid vessel with a muscle flap. (Fig. 9.3a–d)

      A325459_1_En_9_Fig3_HTML.jpg
      Fig. 9.3

      (a) Computed tomographic scan showing more than 270° encasement of common carotid artery by metastatic lymph node. (b) Preoperative carotid angiogram. (c) Detachable balloon to occlude external carotid artery and stenting of internal carotid artery. (d) Poststent angiogram showing lack of flow through eternal carotid artery and patent internal carotid artery
       
    4. 4.
      In case of established carotid blow out, bleeding should be secured with digital pressure of the artery against the spine at the bedside. Transfer of the patient to operating room without controlling major bleeding at the bedside may be fatal. In the operating room, if adequate hemostasis can be achieved by digital pressure or clamping the artery, the patient should be hemodynamically stabilized before further exploration of the neck wound. If the blow out has occurred from a branch of the external carotid, it can be ligated. However in case of blow out of the main vessel (commonly occurring at the region of the carotid bulb), repair is mostly futile as the vessel wall is very fragile owing to the pre-existing tissue conditions. In cases, where the carotid needs to be ligated, it is preferred to ligate the vessel away from the contaminated site to prevent further blow outs. The vessel ends can be covered with muscle tissue for further protection.
      Significant difference has been reported by Moore et al. in the incidence of death and neurological sequel in patients undergoing elective versus emergency ligation of the carotids [30]. They reported 23 % risk of neurologic complications after elective ligation versus 50 % after emergency ligation. The risk of death was 17 % in the elective ligation group versus 38 % in the emergency ligation group. This difference is mainly as a result of massive sudden hemodynamic compromise as a result of carotid blow out.
      Internal jugular vein blow out is much less fatal and managed with either repair or ligation of the vessel.
       
     

9.3.3 Complications Arising During Primary Tumor Resection

  1. 1.
    Planning access to avoid complications during ablation
    Failure to properly plan access for the ablation results in intraoperative complications with failure to obtain a three-dimensional clearance of the tumor.
    Depending on the location of the primary tumor and the deeper extent, the incisions should be planned for accessibility.
    The main consideration is whether the ablation can be done per orally or needs a lip split for access.
    Design of the lip split either incorporating a chevron, step ladder with a Z plasty or along the mental prominence ensures good postoperative cosmesis.
    Skin and mucosal slough can be prevented by planning of incisions to avoid acute angles, atraumatic handling of tissues and planned placement of sutures to avoid devitalizing tissues. It is imperative that incisions be made with a knife and deepened atleast till the dermis prior to using cautery. The division of the muscle fibers along the lip and chin with the skin and dermis ensures good postoperative viability [3133]. (Fig. 9.4a–g)

    A325459_1_En_9_Fig4a_HTML.jpgA325459_1_En_9_Fig4b_HTML.jpg
    Fig. 9.4

    (a) Trifurcation incision breakdown due to non-functioning suction drains that keep the skin flaps adhered to the bed. (b) Improperly designed lower lip split with skin wound dehiscence. (c) Dehiscence at neck wound at multiple points as the flap has failed to obliterate the dead space. (d) Marginal necrosis of the pectoralis major skin paddle. (e) Neck wound dehiscence due to wound infection and contamination from the tracheostomy site. (f) Multiple neck wound dehiscence due to neck haematomas. (g) Neck wound dehiscence due to thin skin flaps especially posteriorly with a deficient platysma muscle
    Access for lesions depending on the site:

    1. (a)
      Buccal mucosa and gingivobuccal sulcus tumors:
      For early T1 and T2 lesions of the buccal mucosa and gingivobuccal sulcus excision can be done through per oral approach with the deeper margin of resection including the buccinator muscle but safeguarding the facial nerve branches. Lesions abutting the mandible need to have a concomitant marginal mandibulectomy done. If the lesion is abutting the upper alveolus, this necessitates either an alveolectomy or an infrastructural maxillectomy.
      While performing a marginal mandibulectomy avoid sharp angles as they are prone to occlusal stresses and subsequent fractures. The angle of the mandible is the area most prone to these forces. Rounding off the angles to obtain a smooth contour prevents the concentration of these unfavorable forces. Preserve atleast 8–10 mm of the lower border of the mandible in marginal mandibulectomy resections (Fig. 9.5a–c).

      A325459_1_En_9_Fig5_HTML.jpg
      Fig. 9.5

      (a) Sharp angles to be avoided in a marginal mandibulectomy that are prone to stress concentration and fracture. (b) Sharp angles to be avoided as these bony spurs can also damage the pedicle of the free flap as it passes along the lingual surface of the mandible. (c) Preserve at least 8–10 mm of the lower border of the mandible to prevent pathologic fracture
      For advanced lesions extending posteriorly to the retromolar trigone or T3 and T4 lesions with involvement of the infratemporal fossa, a lower lip split with a cheek flap gives access to the tumor and infratemporal fossa clearance. Lesions with paramandibular involvement and cortical erosion need a segmental bone resection. Lesions abutting the retromolar trigone have a pattern of spread along the pterygomandibular raphae to the infratemporal fossa. The bone margin should include either a marginal mandibulectomy or a posterior segmental mandibulectomy.
      If the resection includes a mandible angle osteotomy, the proximal and distal fragments are repositioned with a semirigid fixation using a heavy prolene suture rather than plate fixation. The former facilitates a pseudojoint creation which significantly reduces the postoperative trismus [34, 35].
      A lower lip split is also needed in patients with inadequate mouth opening due to submucous fibrosis.
      It is imperative to plan the lip split according to the mucosal or skin margins required depending on the lesion to avoid lip necrosis due to inadequate supply through the inferior labial vessels which get transected. In these instances, an angle split is more appropriate.
       
    2. (b)
      Upper alveolus and gingivobuccal sulcus tumors
      Depending on the location of the tumors, the incisions need to be planned. Lesions requiring clearance of the infratemporal fossa need a lower lip split with a cheek flap. A Weber Ferguson with its modifications and upper cheek flap does not give access to the posterior compartment. Resection of these tumors needs a composite resection of the alveolus, hard palate, soft palate, tonsillar pillars and mucosa depending on the extent and margins needed. Due consideration should be given to the pattern of spread of these tumors along the neurovascular bundle of both the greater palatine and posterior superior alveolar. As these branches of the maxillary nerve (V2) extend into the pterygomaxillary fissure, it is this structure along with the inferior orbital fissure that needs to be assessed preoperatively in scans. Ensuring negative surgical margins along these structures might be difficult in advanced tumors and need to be considered in the inclusion of the treatment portals during postoperative adjuvant radiation [34, 35].
       
    3. (c)
      Tongue tumors
      For early lesions T1 and T2 a per oral glossectomy provides good access. If the floor of the mouth with the mylohyoid diaphragm needs to be removed enbloc, a planned compartment resection is possible through the per oral and neck approach by detaching of the suprahyoid muscles from the hyoid bone. Troublesome bleeding from the lingual artery can be avoided by identifying it and obtaining vascular control before it passes deep to the hyoglossus.
      In advanced T3 and T4 lesions necessitating a total glossectomy, the tumor is delivered transcervically along with the mandible component (marginal or segmental) and once dropped into the neck through a pull-through approach the posterior mucosal and tonsillolingual sulcus extension can be visualized and palpated before placing the cuts.
      Access for lesions on the posterior tongue may necessitate either a lateral pharyngotomy or mandibulotomy approach.
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Jun 24, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Pearls and Pitfalls in Oral Cancer Management
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