Periodontal microsurgery

Periodontal microsurgery is one of the many advances that have taken place in the field of surgical periodontal therapy. Microsurgery is described as a methodology, a modification, and refinement of existing surgical techniques that uses magnification to improve visualization and has implications for and applicability to all specialities1. Historically, the first microsurgery was performed by Carl Nylen, in an eye surgery using a binocular microscope in 1922 2. He is considered as the father of microsurgery. Since its introduction, microscope-assisted medicine has grown exponentially. At present, microsurgery is extensively used in all fields of medicine.

Microsurgery was introduced into dentistry by Apotheker and Jako in 1978 and it was first introduced to the branch of endodontics in 1986 3. Later on, in 1992 the field of periodontology adopted the use of magnification in various surgical procedures 4.

Rationale of microsurgical techniques

There are many advantages of microsurgery over conventional surgeries in terms of precision, reduced trauma and post-operative patient comfort. The rationales in favor of microsurgery include,

  1. The conventional surgeries involve larger area involving more soft and hard tissue manipulation which results in greater post-operative edema, inflammation, and pain. On the other hand, because of their small size, microsurgical instruments reduce the amount of trauma to the tissue, thus reducing post-operative edema, pain, and discomfort.
  2. Gentle handling of the tissue is an important factor deciding the success of periodontal esthetic surgeries. More the tissue is manipulated more the healing is compromised. During the microsurgical procedure, there is minimal manipulation of the tissue which is especially advantageous in periodontal esthetic surgeries.
  3. The blood supply of the operated area is directly related to healing. Microscope guided surgeries allow avoiding certain incisions all together, which helps in better blood perfusion. For example, while harvesting connective tissue graft from the palate, magnification allows placement of the incision line parallel to the cervix of the teeth, avoiding a releasing incision that would deny flap from one source of its blood supply. Moreover, the healing is faster with minimal scar formation.
  4. While performing conventional surgical procedures,…………………

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Principles and elements of microsurgery

Most of the dental treatment rendered historically has been done with the naked eye or macroscopically. In microsurgery, the treatment is rendered under a microscope. It is aimed at improving the operator’s skills and to provide better results in operating those areas where precision and delicacy are required. As a treatment philosophy, it encompasses three principles 5,

  1. Improvement of motor skills, thereby enhancing surgical ability.
  2. An emphasis on passive wound closure with exact primary apposition of the wound edge.
  3. The application of microsurgical instrumentation and suturing to reduce tissue trauma.

There are three primary elements of microsurgery,

These elements are also referred to as microsurgical triad 6.  No microsurgical technique can be done if……………..

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Clinical philosophy:

One needs to practice and attain a level of experience with microsurgical techniques to competently perform various periodontal surgical procedures. A good microsurgery can achieve results which cannot be commonly achieved by regular surgeries. To adapt micro-surgery in regular practice one should be open to new ideas and techniques. One needs to practice precise tissue handling and wound closure suturing technique to master microsurgical techniques.

Hand control during microsurgery

It is important to understand the basic aspects of hand movement before we go into the details of microsurgical techniques. Primarily, long flexor and extensor muscles control the finger movement. The finger movement performed by these muscles is relatively crude but is markedly improved when the wrist is stabilized on a flat surface. The control over finger movements is further improved by placing the wrist in a dorsiflexion position angled approximately at 20 degrees. Muscle tremors are significantly reduced in this position 5, 7.

Physiological tremors:

Physiologic tremor is the uncontrolled movement arising from both the intended and unintended actions of our bodies. Awareness of this effect is further enhanced under magnification. These unwanted hand movements during microsurgery not only compromises the operator’s skill, but also jeopardizes the results of the surgery.  There are many factors affecting physiological tremors, including anxiety, alcohol, smoking, recent exercise, hypoglycemia, caffeine, and medications. To avoid these tremors, microsurgeon should have a relaxed mind, comfortable posture, well-supported hand and stable hold on the instrument. The basic principles of patient and operator positioning as described in chapter 50 “Principles of instrumentation” should be followed. Along with following these principles, additional stabilization of the forearm and wrist are required to perform microsurgery. While performing the surgery, the hand should be directly or indirectly stabilized by establishing a finger rest on the immovable surface. Only the fingertip movement should be performed to make purposeful and deliberate movements.

Instrument grasp

The grasps used in microsurgery are the same as described in chapter 50 “Principles of instrumentation”. Primarily, pen grasp (also known as an internal precision grip) is used for microsurgeries because it provides more stability than any other grasp 8. The fingers make a tripod effect in this position which provides maximum stability to the instrument.

Microsurgical instruments

As the name indicates, microsurgery uses a microscopic magnification of the area to be operated. Along with this microsurgical instruments are used which cause minimum trauma and bleeding during the surgery.

Magnification systems:

Presently, a wide range of simple and complex magnification systems are available for microsurgery. There are basically two types of magnification systems, loupes and surgical operating microscopes.

Loupes:

Dental loupes are the most common system used for optical magnification. These consist of two monocular microscopes with side-by-side lenses angled to focus on one single object. A convergent lens optical system is called as Keplerian optical system. The major disadvantage associated with loupes is that eyes must converge to view an image which causes early eye straining and fatigue. Furthermore, prolonged use of loupes may result in vision change 9. Three types of loupes are commonly used,

  1. Simple loupes
  2. Compound loupes
  3. Prism loupes

Simple loupes:

In these loupes, the magnification is achieved simply by adjustment of the working distance to a set length. It is referred to as diopter magnification. Simple loupes are primitive magnifiers with limited capabilities. The magnification can be increased by increasing the diameter and thickness of the lens. Because of size and weight constraints, it is impractical to get a magnification beyond 1.5X with these loupes. Another problem associated with these loupes is the distortion of image and colors due to the spherical and chromatic aberration of the lens. Hence, these loupes are not preferred by most of the clinicians.

Compound Loupes:

These loupes use multiple lenses with intervening air space to gain additional refracting surfaces (Figure 71.1). These lenses can be adjusted to clinical needs without increasing their size or thickness. The lenses used in compound loupes can be achromatic which improves the optical design. In achromatic lenses,………………………….

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Figure 71.1 Compound loupes

Compound loupes

Prism loupes:

The prism loupes are most advanced loupe magnification systems (Figure 71.2). These contain Schmidt or rooftop prism which lengthens the light path through a series of switch back mirrors between the lenses. This arrangement folds the light so that the barrel of the loupes can be shortened. Furthermore, this arrangement produces better magnification, larger fields of view, wider depths of field, and longer working distances than do other loupes. Because of short barrel of the prism loupes, they can be mounted on eyeglasses or headband. At magnification beyond 3X, headband mounted loupes are more comfortable and stable as compared to the eyeglass mounted loupes. The recent advancement in this magnification system is the addition of coaxial, fiberoptic lighting incorporated in the lens elements to improve illumination (Figure 71.3) 10.

Figure 71.2 Prism Loupes

Prism loupes

Figure 71.3 Coaxial lighted loupes

Coaxial lighted prism loupes

Know more………..

HDTV Single Camera 3D System:

This involves a high definition television attached to the microscope which enables three-dimensional visualization and documentation as well 11. It also allows easy printing, organization of the database and adaption to teleoperations. The stereoscopic image produced can be viewed by multiple persons at the same time, which is an advantage to academicians.

 

Advantages of loupes:

  • These are less expensive.
  • These are easy to use and are less likely to breach a clean operating field.

Limitations of loupes:

  • These provide a limited magnification of the operating field, usually up to Beyond this magnification, the image gets distorted.
  • Most of the loupes do not have an inbuilt light source so an independent light source is required for illumination of the operative
  • In loupes, there is approximately 4% loss of light because of surface refraction, unless anti-reflective coatings are placed on the lenses. In compound and prism loupes, the loss of brightness due to refraction may be up to 50% in the case where anti-reflective coatings are not placed.
  • Loupes are inferior as compared to surgical microscopes when high visual acuity is required.

Surgical microscope:

Surgical microscopes are superior to loupe microscopes in terms of flexibility, visual acuity, and magnification. However, these are much expensive than loupe magnifiers and are more difficult to use initially. The operating microscopes designed for use in dentistry are based on Galilean principles. The magnification provided by these microscopes ranges from 4X to 40X. The components of a surgical microscope are,

  1. Magnification charger
  2. Objective lenses
  3. Binocular tubes
  4. Eyepieces
  5. Lightning unit
  6. Additional attachments

Although surgical microscopes provide greatly improved visual acuity and the control of the surgical instruments, there are some basic problems associated with their use 12. While performing microsurgery, it is often required to…………………..

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TOMS- Three-dimensional on-screen microsurgery system:

The current advances in the field of microsurgery allow visualization of the surgical site directly on the monitor.  The clinician does not necessarily need to physically view through the microscope. The assembly of the TOMS consists of the surgical microscope, to which is attached a three-dimensional on-screen microsurgery system consisting of two single chip video cameras mounted on custom fit eyepiece adapters, a dual camera controller, a view/record image processor, a digital recording system, LCD/LED monitor for viewing the image of the surgical area, synchronizing signal emitter and 120 MHz shutter glasses (stereo eyewear) 13.

Surgical instruments

As a general rule, working end of all the instruments used during microsurgery should be smaller than the regular instruments. For high-quality performance during surgery, the average length of these instruments should be around 15 cm. The body of the instrument should be circular in cross section so that rotation while instrumentation is smooth. The working end or the cutting edge of these instruments should be smaller than that used for regular instruments. The instruments should preferably be made up of titanium, which makes them lighter and more resistant to distortion than regular stainless steel instruments.

In certain situations, instruments used in ophthalmic surgery are utilized. For example, while doing the papilla augmentation procedure, interdental papilla is dissected within the interdental embrasure. This incision is best placed by a “J” shaped ophthalmic blade, which is run under the interdental papilla and separates the tissue from the underlying bone. Once the incision is placed, the mini-flap can be raised by using a small periosteal elevator without tearing it. For stabilizing the tissue small size needle is most efficiently grasped by a small Castroviejo needle holder. The needle holder should have a good grip over the small needle and should not allow its rotation while applying pressure during taking tissue bite. Along with this, the instruments used in microsurgery should be non-reflective to avoid blinding of the operator (especially with the high-intensity light of the microscope) and should be non-magnetic.

Micro-sutures

One of the basic rules in microsurgery is passive wound closure and exact primary apposition of the wound edges. For microsurgery, sutures with size…………………….

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Knot tying is an important part of the surgical procedure in microsurgeries. While placing knot, the operator should be able to fully visualize his/her hands under macroscopic vision. The needle is held in the dominant hand and gloved fingertips of the other hand are used to place the tie using proprioception. The knot is placed by holding the suture with needle holder in the dominant hand and microsurgical tissue pick up in the non-dominant hand. While placing the knot only the tips of the instrument are visible to the operator under magnification.

Limitations of microsurgery (minimally invasive surgery)

Along with all the advantages of microsurgery discussed so far, there are some limitations also. Jaffray (2005) 14 enumerated following limitations of microsurgery,

  1. It requires special equipment,
  2. Specialist training is probably required,
  3. Some additional equipment could be more expensive, and
  4. Some procedures may take longer time than usual, as compared to conventional surgeries.

Review of literature on microsurgery

Many studies have compared the outcome of the conventional surgeries and microsurgical procedures. In one such investigation, Cortellini and Tonetti (2001) 15 evaluated the outcomes of a microsurgical approach in the regenerative therapy of deep intrabony defects in 26 patients. They were treated with regenerative therapy using guided tissue regeneration. The results demonstrated that in 92.3% of the cases wound closure was intact throughout the healing period. The average clinical attachment gain was found to be 5.4 mm which corresponded to 82.8% of the initial intrabony component of the defect. The authors concluded that the use of microsurgical approach was associated with very high ability to obtain and maintain primary closure of the interdental tissues over the barrier membranes.

Another study was done by Wachtel et al. (2003) 16 to assess the clinical effect of the microsurgical access flap and enamel matrix derivatives (EMD) treatment with an emphasis on the evaluation of early wound healing. Patients included in the study had at least one pair of intrabony periodontal defects with an intrabony component of > or =3 mm. The parameters examined at baseline, 6 and 12 months after surgery included the oral hygiene status (API), gingival inflammation (BOP), probing pocket depth (PPD), clinical attachment level (CAL) and gingival recession (GR). The defects were randomly treated with test and control treatments with control treatment of only microsurgical access flap and test treatment of access flap and conditioned with a 24% EDTA gel followed by EMD application. The results of the study showed that in terms of probing pocket depth and clinical attachment gain, the combination with EMD application appeared to be superior to the microsurgical access flap alone.

Harrel et al. (2005) 17 investigated the effect of using EMD in combination with minimally invasive surgery (MIS) in performing regenerative therapy in periodontal defects. The surgical treatment was performed in 160 sites on 16 patients. The results of the study demonstrated that the combination of MIS and EMD resulted in significant reductions in probing depths and improvements in attachment levels while producing little or no increase in recession.

A study done by Cortellini and Tonetti (2007) 18, evaluated clinical performance and patient perception associated with minimally invasive surgical technique in addition to the application of EMD in the treatment of isolated deep intra-bony defects. 13 deep intra-bony periodontal defects in 13 patients were surgically accessed with microsurgical technique. The authors concluded that in addition to a decrease in the surgical time, the technique decreased patient morbidity as the postoperative period was uneventful for 77% of the patients. In yet another study by Cortellini et al. (2008) 19,the clinical performance along with intra-operative and post-operative morbidity associated with minimally invasive surgical technique in addition to EMD application in the treatment of multiple deep intrabony defects in a single surgical procedure was evaluated. 44 defects in 20 patients were evaluated were surgically accessed. The results of the study suggested that MIS could be used in combination with EMD application in a single surgical procedure with excellent clinical outcomes with limited patient morbidity. A similar study was done by Jepsen et al. (2008) 20, where they evaluated and compared the outcomes of a combination of an enamel matrix derivatives and a synthetic bone graft (EMD/SBC) with EMD alone in wide intra-bony defects. The surgical procedure involved microsurgical technique and the modified papilla preservation flap. The results of the study found similar clinical results following both treatment modalities.

A modified minimally invasive surgical technique (M-MIST) was suggested by Cortellini and Tonetti (2009) 21 where only a buccal flap was raised while the interdental papilla was left in situ. The granulation tissue was removed, leaving the interdental and palatal tissues intact. After root instrumentation and placement of regenerative material, primary closure of the flap was achieved with a single internal modified mattress suture. The results of the study demonstrated limited patient morbidity and excellent clinical improvements. However, the authors suggested the requirement of a larger study to confirm the results as this study was done on 15 isolated interproximal defects out of 20 selected ones.

Conclusion

Microsurgical techniques have been shown to improve the treatment outcomes substantially and to a clinically relevant level as compared to conventional macrosurgical techniques. The magnification of the operative field allows the surgeon to view the area closely, facilitating precise and delicate tissue handling. However, the mastering of microsurgical techniques requires special training and practice. In addition, the cost of the equipment and instruments is an additional factor to be considered. New innovations are required in this field to make microsurgical techniques cost effective for both the dentist and the patient.

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References:

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Periobasics: A textbook of periodontics and implantology

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