Patient-specific soft tissue reconstruction: an IDEAL stage I report of hemiglossectomy reconstruction and introduction of the PANSOFOS flap

Abstract

The standard of care for head and neck reconstruction is microvascular free-tissue transfer. Various techniques of soft tissue, free-flap design have previously been described. Patient-specific planning and 3D printing have changed practice in bony reconstruction, but are not currently used in soft tissue head and neck reconstruction. We present the first report of P ersonalised p A tient-specific pla N ning of SOF t tissue rec O n S truction, the “PANSOFOS” flap, and aim to prove that the technique has a place in soft tissue reconstruction of the head and neck. Using the IDEAL framework for the reporting of surgical innovations (IDEAL stage 1, proof of concept report), we describe the case of a patient with oral cancer who had reconstruction of the tongue after hemiglossectomy. The staging scans, 3D printer and software were used to create a soft silicon resection guide and flap harvesting guide. The 3D guide was then used to design a 2D outline of the perimeter of the flap, and a negative silicone mould used to control its bulk. The procedure was successful and the postoperative period uneventful. The oncological, cosmetic, and functional outcomes were excellent. The patient followed the local enhanced recovery pathway and was discharged home with safe swallowing. This report confirms that patient-specific 3D planning can be used in the reconstruction of soft tissue defects of the head and neck. We aim to develop the technique using the next stages of the IDEAL framework, and anticipate that the PANSOFOS flap will become a standard of care.

Introduction

Head and neck cancer is the sixth most common type of cancer worldwide. Oral cancer accounts for up to 40% of its burden, and remains a challenge to treat. The mainstream treatment is ablative surgery and appropriate reconstruction followed by adjuvant radiotherapy (with or without concurrent chemotherapy), if indicated.

The ablation of oral cancer often involves combined excision of oral mucosa and musculature, as well as bone and cartilage. Occasionally this includes the sacrifice of important neurovascular structures, so the resulting defects are complex and can lead to anatomical distortion that has a detrimental effect on speech, swallowing, mastication, and cosmesis. Reconstruction should aim to maximise precision and achieve optimal function, as this will aid the patient’s rehabilitation and improve their quality of life.

The standard of care in head and neck reconstructive surgery is microvascular free tissue transfer. Various techniques (such as “snoopy head”, conical, and bilobed) for the shaping and fashioning of a soft tissue free flap to fit the defect have previously been described. All, however, share the same drawback: they are not personalised to the patient and the defect, and consequently lack precision and accuracy.

Over the last few years, 3D printer technology and patient-specific planning (PSP) have revolutionised bony head and neck reconstruction. This has resulted in a reduction in operating time and excellent cosmesis, and has allowed dental rehabilitation in an increasing number of cases. The philosophy is simple: the resection/ablation is guided by specific laboratory-made guides using the patient’s own data from the staging scans. This is then followed by bony reconstruction using a guide to harvest the free flap with maximum accuracy. Despite these advances, however, practice in soft tissue reconstruction of the head and neck has changed little. We strongly believe that this is an area in which the same (and potentially more) advantages may apply. Studies on breast surgery have suggested the use of 3D templates to establish the shape and volume of free flaps, and initial results have been promising. Ideally these principles should also apply to soft tissue reconstruction of the head and neck.

We present the first report of P ersonalised p A tient-specific pla N ning of SOF t tissue rec O n S truction in head and neck surgery, and have coined the term “ PANSOFOS ” flap to aid future reference. We have used the IDEAL framework for the reporting of surgical innovation techniques, which summarises the stages through which interventional (surgical) innovation normally passes. This study is an IDEAL stage 1, proof of concept report.

Stage I (Innovation)

Purpose

The purpose of the current report is to describe the use of personalised patient-specific planning with 3D printer technology, staging scans, and guides in a patient who had reconstruction of the tongue after hemiglossectomy for oral cancer. To our knowledge, this is the first detailed presentation of such a case in the medical literature. The initial idea was generated by one of the authors (HK) who shared his experience of breast reconstructive surgery. We aim to follow the stages of the IDEAL framework throughout the process of developing the technique and to prove that PSP can and should apply in soft tissue reconstruction of the head and neck; that there are considerable benefits for the patient when it comes to cosmesis and function, that the technique is cost-effective, and that there is scope for further development.

In particular, this study aims to find out whether 3D printing technology can:

  • 1.

    Accurately make use of the surgeon’s preoperative plan to copy the excised (predicted) soft tissue (using data from staging scans)

  • 2.

    Produce a negative analogue/mould of the excised soft tissue

  • 3.

    Accurately indicate the shape and the volume of the harvested free flap that would be used to reconstruct the defect

  • 4.

    Record theatre times, surgical complications, and hospital stay

  • 5.

    Improve swallowing outcomes and reduce the number of patients who depend on a tube.

Output/outcomes

Reconstruction of a hemiglossectomy defect is usually straightforward and some surgeons would argue that no planning is needed. This might be true in simple cases, but it is also true that simple cases are ideal for providing proof of concept for the main aim of this surgical endeavour: state-of-the-art reconstruction of complex soft tissue defects in the head and neck (for example, posterior tongue extending to the retromolar trigone, soft palate-oropharynx, etc).

The functional success of this type of reconstruction is mainly evaluated by objective assessments of speech and swallowing outcomes, which are done by the speech and language assessment team (SALT). A lack of flap-related surgical complications (failure, return to theatre, fistulas, or leaks) is also an indicator of technical success. The rationale behind the concept is that the more accurate the reconstruction, the better the postoperative functional outcome will be, with fewer complications.

Surgical team

A single OMFS head and neck surgeon (PK) with a long experience of microvascular free-flap reconstruction (over 400 cases) led the case described here. PK performed the tumour ablation using the 3D printed guide, harvested the radial forearm free flap (RFFF) with the aid of the flap guide, and inset the flap. Microvascular anastomosis was done in a standard way: the facial artery was hand-sewn end-to-end to the radial artery, and the conjoined vein (venae comitantes and cephalic) joined end-to-end to the common facial vein with the use of a coupling device. PK operated jointly with a second OMFS head and neck consultant according to the British Association of Head and Neck Oncologists’ (BAHNO) guidelines, and was assisted by a group of senior and junior trainees. A reconstructive scientist (OB) from the maxillofacial laboratory supported the case from beginning to end.

Case report

Planning technique

A 78-year-old man presented with a cT3N0M0 squamous cell carcinoma of the right oral tongue (American Joint Committee on Cancer (AJCC) 8 th edition). His case was discussed by the head and neck multidisciplinary team and he was offered radical surgery, reconstruction, and adjuvant radiotherapy, with curative intent.

Using data from the staging scans uploaded in the Materialise software (Mimics inPrint 3.0, ProPlan CMF 2.1 and 3-matic Medical 14.0), PK developed a plan for ablation that aimed for a R0 excision of tumour. It included a right hemiglossectomy and excision of the floor of the mouth up to the attached lingual gingiva. The resection plan included the mylohyoid muscle and ipsilateral hypoglossal nerve.

The scan that was used for the plan was a 0.5 mm computed tomogram (CT) of the head, neck, and thorax. This ensured detailed resolution that allowed for the creation of a high-quality model for 3D planning. As previously described, DICOM files from the scan were transformed into stereolithographic (STL) 3D models of the patient’s hard and soft tissues ( Fig. 1 ). The anatomical areas of interest (tongue, floor of mouth, mandible, and hyoid bone) were then separated to enable accurate resection planning, and the software allowed for the removal of dental artefacts. The 3D models were then exported into ProPlan CMF software (Materialise), and the surgeon marked out the area of resection.

Aug 5, 2020 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Patient-specific soft tissue reconstruction: an IDEAL stage I report of hemiglossectomy reconstruction and introduction of the PANSOFOS flap
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