Journal of Multidisciplinary
Dental Research

Principles of microsurgery

• Improved motor skills, enhancing surgical ability.

• Passive wound closure with primary apposition of the wound edge.

• Micro surgical instrumentation and suturing in reducing tissue trauma.

Ergonomic in microsurgery

The operator must be in relaxed, with comfortable body posture, supported hand, and a stable hold on instrument. ³ Figure 1

To accomplish precise finger movements, the ulnar surface of the forearm and wrist should be supported on a flat surface, and angled at approximately 20° to reduce muscle tremor. ^4, 5

The operator is seated upright (back straight and head erect) with feet flat on floor and thighs parallel to the floor. If the patient's head is assumed in the 12 o'clock position in front of and perpendicular to microsurgeon's chest, the most precise rotary suturing movement for a right handed person is from the 2 o'clock to the 7 o'clock position, while for left-handed people it is from the 10 o'clock to the 4 o'clock position. The forearm should be slightly supine, positioning the knuckles away from clinician, so that the ulnar border of his/her hand, wrist, and the elbow are all well-supported, allowing the weight of the hand to be on the ulnar border.

The most commonly used finger grip for micro-surgical procedures is pen grip also known as internal precision grip [Figure 2]. ^4, 6

Therefore, beneficial ergonomic aspect of magnification technique including diminished shoulder, neck, and back problems, improved vision, and reduced eye fatigue ^7, 8 may be the most influential factors in its adoption by the dental profession at large scale.

Achieved through fibreoptic technology, improves the method of focusing light on site of interest which is an important feature of surgical microscopes.

Magnification

Can be achieved by using loupes and operating microscope. One should know the optical principles under which the loupes work namely Working distance, Depth of field, Width of field /field of view, Viewing angle, Magnification. Most periodontists find 2.5X magnification appropriate.

Based on these principles there are 2 mechanism under which it works.

• Keplerian optics: Here it has 2 lenses where it angled to focus an object. Loupes works on this mechanics. (Figure 3 a)

• Gallilean optics: It have binocular eyepiece which is joined by offset prisms to establish a parallel optical axis & permit stereoscopic vision without any eye strain and convergence. (Figure 3 b). 9

Increased precision in the surgical skills

The third component of microsurgical triad, is the synergistic result of illumination and magnification.

Magnifying instruments

(Table 1 and Figure 4 )

• Loupes

• Simple loupes

• Compound loupes

• Prism loupes

2. Operating microscope

Microneedle Holder

The length of most commonly used micro needle holder are 14 cm and 18 cm. The needle holder tip can be straight or gently curved. The nature of the suture determines the choice of the needle holder. Usually a minute tip (0.3 mm) is used for 8-0 and 10-0 sutures. The needle holder with a 1-mm tip is used for 5-0 and 6-0 sutures. ¹⁴ A needle holder should ensure that a needle is held steadily without slipping.

Micro forceps

Micro forceps can make those manoeuvres that cannot be performed by hand. The most popularly used micro forceps are 15 cm long, with round handles and 0.2- to 0.3-mm tips.

There are variety of Micro forceps for different operations.

• Straight Jeweller Forceps

• Curved Jeweller Forceps

Jeweller forceps are strong and cheap, with a variety of tips available. They can be classified as straight or curved at different degrees, such as 45° or 90°. They are usually 11–12 cm long and suitable only for superficial operations. Their handles are flat, which makes rotating and changing the direction of the instrument less efficient.

Micro scissors

These are used for dissection of tissues, blood vessels, and nerves. Most commonly used scissors are 9cm, 14 cm and 18 cm long. The tips of the scissor blades are of two types, straight and curved. Straight scissors are used to cut sutures and Curved scissors dissect vessels and nerves.

Surgical Knives

Surgical knives are extremely sharp and small in size. ¹⁴ Compared with the standard 15 blades commonly used in periodontics, the smaller size of the ophthalmic knives facilitates surgical work. ¹⁵

• Blade-breaker knife has an ophthalmic razor blade affixed to its a handle. This is used in place of a no. 15 blade. ¹⁶

• The Crescent knife is used for intrasulcular procedures. It can be used in connective tissue graft procedures to tunnel, to prepare the recipient site, or to obtain the donor graft.

• The Spoon knife is used to undermine the sulcular region in preparation for grafts site in regenerative surgical procedures. ¹⁵

Recently developed instrument system of interchangeable blades and handles for flexible and efficient work is Feather Microsurgical Blades, which are made of high-quality stainless steel using high-precision grinding technology producing ultra-sharp cutting edges which allows pricise incision and minimize the risk of tissue injury. All blades are gamma-sterilized. The handles are available in different shapes and sizes. (Figure 8 )

Microsurgery Needles

Vary in size, shape and curvature, but most needles used in dental procedures are of 3/8 curvature. A reverse cutting needle of size 16 to 19mm is used most commonly in periodontal surgery.

Example is Spatula needle, 6.6mm in length and curvature of 140 degrees, allowing precise apposition, closure, and immobilization of the soft tissue graft. ¹⁶

Basic Suturing Techniques

Accurate dissection & suturing of tissues under the microscope depends on visual feedback which is affected by:

• Magnification

• Lighting intensity

• Glare

• Colour contrast

• Other visual features, including visual health, binocularity, trained perception, skill, experience & fatigue

When variable magnification is available, higher magnification is used to place sutures & lower magnification to knot the sutures. Finer needles & suture materials are used in microsurgery, which, in turn, demand precision miniaturized needle holders & tissue forceps to handle the tissue gently for precise positioning. A skilled microsurgeon uses proper basic suturing techniques & skills as a foundation for the advanced techniques. ¹³

Suture geometry

• Angle of needle entry and exit should be slightly less than 90 degrees

• Bite size of suture should be approximately 1 5 times the thickness of the tissue

• Equal bite sizes on either side of the wound

• Needle passage should be perpendicular to the wound

Knot Tying

Knot tying using the microscope is done using a microsurgical needle holder in the dominant hand and a microsurgical tissue pick up in the non-dominant hand. The working tip of the instruments only is visible in the microscopic field. Well tied microsurgical knots are stable and resist loosening, even under functional load. ⁶

Ideal Needle–Thread Combination (Non -Resorbable) for use in Periodontal Microsurgery

• For buccal releasing incision following combinations can be used:

• A suture made up polypropylene (Prolene) of gauge 7-0, with the needle having a 3/8th curvature, cutting needle with precision tip and a length of 7.6 mm.

• A suture made up polypropylene (Prolene) of gauge 7-0, with asymptomatic curved needle, cutting needle tip with round body and a length of 8.9 mm.

• A suture made up polyamide (Ethilon) of gauge 9-0 with a spatula needle having a 3/8th curvature and a length of 5.2 mm.

2. In anterior areas interdental sutures can be placed with the following:

• A suture made up Polypropylene (Prolene) of gauge 6-0, with the needle having a 3/8th curvature, cutting needle with precision tip and a length of 11.2 mm.

• A suture made of Polyamide (Ethicon) of gauge 7-0, with the needle having a 3/8th curvature, cutting needle with precision tip & length of 11.2 mm.

Clinical applications

Periodontal microsurgery is the descendant of conventional periodontal surgery in an attempt to reduce the surgical trauma and opens the horizons for better patient care. (Table 3 and Figure 9 and Figure 10 )

Table 3: Differences between Traditional technique and Minimally invasive surgery (MIS) in periodontal surgeries ¹⁰

1. Root surface debridement

This procedure is an essential component of periodontal therapy. ¹⁷ It is effective when done under illumination ¹⁸ along with an improved early healing index and less postoperative pain ¹⁹ and with micro ultrasonic instruments. The smaller size 0.2–0.6 mm in diameter and variable power settings 25,000 to more than 40,000 cycles per second of these instruments allows subgingival treatment in deep pockets. ²⁰ Moreover, these instruments have active working sides on all surfaces; deliver ultrasonically activated lavage in the working area and can be used with minimal water spray.

2. Periodontal Regeneration

Microsurgical approach is used for the treatment of isolated or multiple intrabony defects. Isolated interproximal defects that are usually limited to interproximal site are considered ideal for bone grafting with Minimally Invasive Periodontal Surgery (MIPS).

Recently, a novel microsurgical approach for periodontal regeneration “Entire Papilla Preservation Technique” (EPP) technique is used,where an interdental tunnel is made through the defect associated papilla by a beveled vertical releasing incision in the buccal gingiva of the adjacent interdental space. ²¹ After removing granulation tissue and debridement of root surface, regenerative materials such as bone grafts and enamel matrix derivative is applied.

3. Mucogingival Surgery

Trained and skilled Periodontal Micro surgeon offers an evident positive result in root coverage procedures ²² and interdental papilla augmentation. ²³ Microsurgical techniques have been shown to offer many advantages when compared with conventional macrosurgical techniques for treating gingival recession. Using micro surgical techniques, increases vascularity of the graft, ²⁴ relatively enhanced root coverage, ²⁴ a efficient increase in thickness and width of keratinized tissue, ²⁵ an appreciable esthetic outcome, with decreased patient morbidity ²⁶

4. Implant Therapy

Different stages of implant treatment ranging from implant placement to implant recovery and peri‑implantitis management is done with more precision under magnification. ²⁷ One of the novel applications of microsurgery is in the sinus lift procedure with a success rate of 97%. ²⁸ The surgical microscope can aid indirect visualization of the sinus membrane and minimizes the risk of perforations.

5. Crown Lengthening

Comparative studies of crown lengthening and ridge augmentation ²⁹ with microsurgical methods are limited, still it is evident that magnification is beneficial in such procedures.

i. Infection control

Magnifying loupes get deposited with debris from various dental procedures. Ideally, all areas of loupe should be disinfected with high level disinfectant after every patient. Disinfecting with high ethyl alcohol solution is popularly recommended. If they are water resistant, Lysol disinfectant spray must be sprayed into a gauge sponge and used to wipe the frames and lenses.

ii. Advancement

Recent advances in microsurgery include 3D on‑screen microsurgery system ( allowing three‑dimensional view of the working surgical field on a video monitor obviating the need of direct physical visualization) HDTV single camera 3D system ( involves attachment of a high‑definition display with microscope) ³⁰ and mechanical optical rotating assembly interface allows the clinician to work at different seating positions.

iii. Disadvantages

Disadvantages include restricted areas of vision, loss in depth of field and visual reference point, steep learning curve, and a relatively higher initial cost of microsurgical setup.