7: An Oral and Maxillofacial Surgeon’s Role in Advanced MDI Therapeutics

Chapter 7 An Oral and Maxillofacial Surgeon’s Role in Advanced MDI Therapeutics

Engineering Assisted Surgery™, MDIs in Functional Reconstructive Surgery Within Great Britain and New Zealand Venues

Outline

Engineering Assisted Surgery™ (EAS) Medical Art and Surgical Craft

Logistical Considerations

Functional Reconstruction

The Art and Craft of Clinical Practice

Successful Outcome

Medical Negligence

Applications of EAS in Healthcare

Head and Neck Surgery: Cost of Treatment

Resource Implications

Indications For EAS

Projections of Cost Savings in Clinical Practice

Application Of EAS to the Healthcare Industry

EAS: Oral and Maxillofacial Surgery Model

Case Discussion 1: Marginal Mandibulectomy and Concomitant Reconstruction of the Dentition with an MDI Technique

Case Discussion 2: The Management of Major Facial Trauma with a Combined EAS/MDI Technique

Reconstruction of the Midface

Case Discussion 3: Maxillary Atrophy

Case Discussion 4 Maxillary Atrophy

Sleeping MDI Implants

Case Discussion 5 Customized Hybrid Implant Systems

Case Discussion 6 Panfacial Resection and Reconstruction

Conclusion

Acknowledgments

Engineering Assisted Surgery™ (EAS) Medical Art and Surgical Craft

Successful clinical interventions rely heavily on human qualities of the clinician and an association with inaccurate replication and transfer of the treatment plans into patients in three dimensions. Clinical outcomes must vary as a consequence of the inconsistencies related to planning, human, and therapeutic trauma variables. Healthcare modernization has not as yet mirrored what was achieved in the 1960s by the manufacturing industry, which achieved modernization of management, service delivery, standardization of quality, reduction in human error, and improved ergonomics, by the rapid assimilation of state of the art technology and automation.

Engineering Assisted Surgery™ (EAS) may be defined as “the application of industrial and engineering systems to healthcare delivery”15 with respect to existing interventions and new and evolving surgical procedures and includes:

EAS heralds new gold standards in the provision of global healthcare with an improvement in efficiency, quality, and outcome, already seen in other industries, and promotes the concept of best practice. The value of an industrial contribution to healthcare modernization has been now recognized. However, such a process can only be effectively implemented within an EAS center of excellence and in partnership with concomitant reforms in healthcare management and delivery, without which healthcare modernization will be ineffective. EAS provides an evidence-based and efficacious industrial model on which to build a modernized National Health Service (NHS) and requires utmost priority within the modernization process.

Functional Reconstruction

Functional reconstruction—i.e., accurate replication of volume, contour, and function of hard and soft tissues—is impossible to achieve with living donor tissue, especially in those cases involving replication of complex osseous anatomy.

Mini Dental Implants

The introduction of Dr. Victor Sendax’s concept of a mini dental implant (MDI) system17,18,19,20,21 has produced a major impact in tissue engineering techniques employed in otolaryngology/head and neck surgery, craniomaxillofacial surgery, and oral and maxillofacial reconstructive surgery.

Indications for the Use of MDIs

Surgical Considerations

Five-year survival rates for patients with advanced squamous cell carcinoma of the oral cavity are poor and have not improved significantly in the past 30 years.1,13 Current treatment modalities are:

Although there have been significant advances in free flap tissue transfer, especially in the reconstruction of the hemimandible and anterior mandible, the introduction of techniques such as the free fibula flap has an association with both donor and recipient site morbidity, cumulating in the disaster of flap loss and loss of the patient (Figure 7-2).

Patients with oral cancer are commonly debilitated and are more likely to have higher American Joint Committee on Cancer (AJCC) fitness scores.3 The implications are that this group of patients is more likely to succumb to the consequences of major surgery. Therefore offering patients treatment options involving reduced surgical trauma has distinct advantages (Table 7-1).

TABLE 7-1 AJCC Fitness Scores

AJCC (H) Performance Scale Definition
H0 Normal activity
H1 Symptomatic and ambulatory
H2 Ambulatory > 50% of time
Occasionally needs assistance
H3 Ambulatory < 50% of time
Nursing care required
H4 Bedridden
May need hospitalization

Moreover, major surgical treatment modalities are costly to the purchasers of healthcare, and if neither cure nor adequate palliation can be achieved at reasonable cost, the value of such treatment protocols requires reappraisal.22

Indications: MDI Implants in Oral Rehabilitation?

Anatomical Considerations

Atrophic Ridges

Factors Influencing Functional Dentition

The 1998 Adult Dental Health Survey (Oral Health)26 in the United Kingdom documented that a minimum of 21 teeth are required for functioning dentition (Figure 7-3).

In a base sample size of 923 adults with dental prostheses, speaking difficulties (9%), eating difficulties (37%), and other problems (16%) were recorded. An overall incidence of prosthetic problems was documented in 40% of patients sampled (Tables 7-3 to 7-6).

TABLE 7-3 Problems with Speaking with Dentures

Problem with Speaking Percentage
Loose denture/slips when talking 4%
Alters or slurs speech 3%
Other speaking problems 2%
No problems 93%

Data modified from Adult Dental Health Survey Oral Health in the United Kingdom 1998. Office for National Statistics; London: The Stationery Office.

TABLE 7-4 Problems with Eating with Dentures

Problems with Eating Percentage
Food sticks under denture plate 12%
Loose/denture/slips when eating 9%
Hurts gums 8%
Cannot chew or bite well 5%
Other eating problems 3%
No problems 74%

36% of patients have eating difficulties.

Data modified from Adult Dental Health Survey Oral Health in the United Kingdom 1998. Office for National Statistics; London: The Stationery Office.

TABLE 7-5 Other Denture Problems

Other Denture Problems Percentage
Loose dentures 5%
Gets ulcers 3%
Sore gum/plate rubs gums 3%
Denture worn down 1%
Other denture problem 4%
No problems 84%

16% of patients have other denture problems.

Data modified from Adult Dental Health Survey Oral Health in the United Kingdom 1998. Office for National Statistics; London: The Stationery Office.

TABLE 7-6 Prosthetic Outcomes

Prosthetic Outcome Percentage
Prosthetic problems (incidents) 40%
No problems 60%

Data modified from Adult Dental Health Survey Oral Health in the United Kingdom 1998. Office for National Statistics; London: The Stationery Office.

The implications of this survey imply that conventional prosthetic practice is delivering a quality of service with a 40% complication rate in the United Kingdom, and current primary treatment options require reappraisal in the light of recent technical advances in the sphere of MDI dentistry.

Because stability of the lower denture is now so effective with inexpensive MDIs and outcomes so superior (compared with the tissue-borne full lower denture prosthesis, which is indicated only if dental implant placement is contraindicated), Peckitt now advocates that the MDI-retained lower overdenture is now the primary denture treatment option.22

MDIs and Complex Maxillofacial Reconstruction

If we consider the 40% prosthetic complication rate for routine edentulous cases, it is clear that more complex cases will present greater problems for the prosthetician, and it is advocated that a simple reliable cost effect system is required. Peckitt argues that MDIs fulfill many of the requirements:

Contraindications to the Use of MDIs

There are few, but include:

Medical Psychiatric disease
  Chronic facial pain syndromes
  History of infected endocarditis
  Rheumatic fever

Rheumatic fever is not necessarily a contraindication; some cases may be deemed low risk. Treatment should be carried out in conjunction with a cardiology opinion. Echocardiography is a useful investigation in the assessment of risk.

Surgical Severe jaw atrophy (bone height)
  Grade 4 bone density (not necessarily)
  Heavy occlusion that cannot be relieved
  Gross dental sepsis
  Immediate tooth replacement after extraction may present problems

Peckitt has demonstrated the successful use of MDI implants in severe maxillary atrophy16 and in grade 4 bone density in conjunction with bone grafting and platelet rich plasma techniques,12 with stability at 9 years.

Management of the Complex Reconstruction Case

Applications of EAS in Healthcare

Let us therefore examine the effects of EAS on the delivery of healthcare on the available evidence.

Head and Neck Surgery: Cost of Treatment15

Average Costs of Treatment: One Live Patient at 2 years

The average cost of a 2-year survival episode is documented at ≤85,000 (USD $132,000) for patients treated with complex composite microvascular techniques (assuming a 70% 2-year mortality rate at ≤25,000 (USD $38,900) per case in line with Lavery’s estimation). In a pilot study of seven patients with cancer treated in Doncaster Royal Infirmary with customized titanium implants,15 zero mortality was recorded at 4.5 years at a cost of ≤14,535 (USD $22,600) per case episode for those patients treated 1994 to 1996.

Complex composite microvascular flap reconstructive techniques are reserved for patients with advanced disease, the majority of which affect the mandible. If the percentage of cases presenting as T3/T4 cases of 28% is accepted, approximately 725 microvascular oral reconstruction episodes per year are carried out in the United Kingdom, at an annual cost of ≤18,125,000 (USD $28,206,000) (assuming the estimated cost of ≤25,000 (USD $38,9000) per episode has remained unchanged since 1993).15

The cost of free flap surgery in New Zealand has been estimated at NZ $60,000 to NZ $80,000 per case intervention (Izzard: 2007 Auckland Head and Neck Cancer Centre) (Table 7-8).

TABLE 7-8 Cost Comparison: Composite Free Flap Transfer Versus Engineering Assisted Surgery (EAS)

Composite Free Flap Transfer EAS
≤25,000 (USD $38,900)/case ≤14,535 (USD $22,600)/case (7 patients)
70% expected mortality @ 2 years 0% mortality @ 4 years
Average cost: 2 year survival ≤85,000 (USD $132,000) Average cost: 2 year survival ≤14,535 (USD $22,600)

Data from Peckitt: EAS Costs 1994-1996. Doncaster Royal Infirmary, United Kingdom, www.maxfac.com/costsavings.html.

Simplification of treatment plans incorporating (EAS techniques has demonstrated a reduction in cost (see Table 7-2) of treatment to ≤14,535 (USD $22,600) per surgical intervention and, in comparison, the national annual total cost of treatment would be ≤10,537,875 (USD $16,399,000) for this option, an annual saving to the nation of ≤7,587,125 (USD $11,807,000) plus an associated improvement in long-term overall mortality figures and statistical significance even on a small sample size.

Research and Development

The palliative care of patients with head and neck cancer is discussed by Lovel,11 who quotes Stjernsward: “No further research is required; the knowledge of what needs to be done exists. The single most useful thing that we can do is to make sure that every patient benefits from that knowledge.”

However, “If surgical treatment is a component of such palliation, it is argued that there is still much to learn” (Peckitt).15

EAS: Discussion

New developments in engineering, used for the first time in oral and maxillofacial surgery,15,22 permit the manufacture of accurate anatomical biomodels of the skeleton from CT scans, using a variety of reverse engineering methods. Biomodels have been used in treatment planning and the design and manufacture of customized titanium implants for the single staged reconstruction of the orofacial region using very simple cost effective interventions. These may carried out without surgery from a second surgical site and obviate the necessity for complex flap surgery.

In our experience, the Sendax MDI system has a pivotal role in complex orofacial reconstruction within the context of EAS. The system is a great example of EAS thinking.

We now have a treatment option that permits endosseous stabilization of a prosthetic device:

Moreover, the Sendax MDI system can be used in conjunction with anatomical biomodels and custom drill guides for precision placement. We have also used the MDI O-ring system in conjunction with customized implant manufacture where conventional MDI placement has been impossible, and we have used this method to replace the whole maxilla and midface in a surgery time of 1.5 hours and with patient discharge at 20 hours (i.e., same-day surgery).

With EAS planning techniques and relatively atraumatic surgical protocols, a single staged orofacial reconstruction, including the dentition, is now possible in most cases, obviating the need for multistaged and increasingly expensive treatment options for patients with a guarded prognosis.

The use of the Sendax MDI system has been so successful in head and neck reconstructive surgery practice in New Zealand that it is rapidly becoming the implant system of choice for this group of patients.

Within oral and maxillofacial surgery, EAS has special relevance in the planning and treatment of complex trauma, facial deformity, craniofacial/skull base surgery, and reconstructive surgery.

Applications are possible in many surgical disciplines, especially orthopaedic trauma, treatment of deformity, and orthopaedic implants, including customized joint replacement. EAS technology permits the design and manufacture of customized implants to an accuracy not before possible. Applications pertaining to medicolegal practice, the demonstration of personal injury, and audit of outcomes, herald new standards in duty of care, and there are applications in high-risk procedures in which precision is of primary importance (e.g., in spinal surgery, where surgical precision could be improved with position and cutting jigs).

As this technology is development and mastered, reappraisal of the principles of surgery in general are warranted, especially in relation to the incredible accuracy that is possible using these techniques and the potential of the elimination of operator error.

EAS: Oral and Maxillofacial Surgery Model

In maxillofacial surgery, EAS techniques have been shown to facilitate:

MDIs and Mandibular Reconstruction

It has long been known within the sphere of dental surgery that the oral cavity has the ability to heal by secondary intention without complication, even in the environment of hostile sepsis. Postextraction sockets illustrate this “par excellence” and yet this innate gift is ill recognized by those providing reconstructive services within this hostile oral environment. This situation has led to the generation and propagation of myths and guidelines on the requirements for oral healing that have in reality no basis in fact or experience (Figure 7-4).

It would appear that vascularized bone irrespective of periosteal cover has the ability to encourage reepithelialization within 7 to 10 days in the oral and nasal cavities.

Reepithelialization produces an attached mucosa that is relatively immobile compared with the surrounding reflected mucosa tissue. This tissue provides an excellent epithelial cuff around implant abutments and gives a superior outcome than epithelial cuffs associated with relatively bulky intraoral flaps, especially free flaps.

This implies that flaps are not required to effect oral mucosa closure and regeneration, in the same way that a flap is not required to close a tooth socket after extraction. This contention is supported by our experience in the management of:

The routine use of flaps for bone cover in the oral cavity must be questioned.

It is advocated that the use of intraoral flapless reconstruction techniques prevents the development of the so-called “Burger Syndrome” in which bulky patty-sized intraoral flaps prevent the effective oral rehabilitation so often impossible in these cases and yet necessary for the maintenance of an adequate quality of life. This is especially important in palliative cases, where outcomes often do not always represent an improvement of morbidity.

The introduction of EAS planning techniques in conjunction with the Sendax MDI system greatly simplifies orofacial reconstruction, making single staged reconstruction possible for most patients.

This has major effects on:

Anterior Rim Sparing Mandibulectomy

The basis of this procedure is that the lingual periosteum acts as a barrier for tumor invasion from the floor of the mouth and gingiva; the edentulous mandible is invaded through the superior aspect of alveolar crest. The tumor invades the mandible as far as the inferior dental canal and then spreads in an anteroposterior direction along the inferior dental canal but rarely below it. Therefore a localized mandibulectomy, sparing the lower mandibular border, may result in tumor clearance.

In a nonatrophic or dentate case, marginal resection of the hemi/anterior mandible and the assessment of residual alveolar height will determine the feasibility of the use of MDIs.

The concept using of the Sendax MDI system to stabilize an immediate overdenture at the time of marginal mandibulectomy has its origin in the use of the system for stabilizing an immediate lower dental prosthesis after a lower dental clearance.

In end-stage periodontal disease, the alveolar bone has often resorbed to the degree that very little alveolectomy is required to trim the bone to the level of the tooth apices. After this task has been performed, MDIs can be simply placed, and gingival margins appropriately trimmed and sutured for healing by primary intention around the emerging implant abutments. A localizing hard resin impression is straightforward, and this is now the method of choice for stabilizing the full lower immediate removable dental prosthesis.

The procedure is simple, reliable, and well tolerated by patients. The outcome is a positive life changing experience for patients, who otherwise would be condemned to a lifestyle of unstable prosthetic dentistry.

In marginal mandibulectomy, the dental clearance is carried out, only this time with an oscillating saw and the dental clearance concomitantly with the jaw resection.

CASE Discussion 1

Marginal Mandibulectomy and Concomitant Reconstruction of the Dentition with an MDI Technique

An 82-year-old woman presented with a well differentiated squamous cell carcinoma of the gingiva.

Past Medical History: Poorly controlled hypertension (Figures 7-5 and 7-6).

Jan 7, 2015 | Posted by in Implantology | Comments Off on 7: An Oral and Maxillofacial Surgeon’s Role in Advanced MDI Therapeutics
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