Advanced Arthroscopy of the Temporomandibular Joint

Patient selection for advanced operative arthroscopy

Indications

Advanced operative arthroscopic procedures are indicated for disabling joint conditions refractory to medical management and primary arthroscopy alone and that require internal structural modifications of the temporomandibular joint (TMJ). Examples include internal derangements, hypomobility secondary to adhesions, synovitis, degenerative joint disease, and hypermobility resulting in painful subluxation or dislocation.

Contraindications

Contraindications include skin infection, possible tumor seeding, and medical and other circumstances unique to patients.

Diagnosis Procedures
Wilkes II, III, early IV stages Arthroscopic discopexy
Wilkes late IV stage Arthroscopic debridement, lysis and lavage
Wilkes V Arthroscopic debridement
Ankylosing osteoarthrosis Arthroscopic debridement
Mandibular hypermobility Scar contracture
Synovitis Arthroscopic lysis and lavage, synovectomy, instillation of medicaments

Armamentarium for advanced TMJ arthroscopy

Basic Armamentarium

Arthroscope

Arthroscopes are available from several suppliers but share similar features. The arthroscope should be less than 2 mm in diameter with an angle of view of 30°. The focal distance should be 0 to infinity. This specification is an absolutely key point because scopes that have focal lengths greater than 1 mm do not permit adequate visualization during advanced arthroscopy ( Fig. 1 ). Other important factors are resolution or sharpness of the image, distortion and flatness of the field, color response, and brightness. The light source should be capable of providing 5000 K color temperature. The arthroscope is a delicate instrument, not to be used in the same manner as a surgical tool. Although the housing is made of materials, such as aluminum and steel, the internal lens components are glass rods, some as small as 1 mm in diameter. A cracked or chipped lens may damage the arthroscope beyond repair. Awareness of the delicacy of the instrument and careful handling is the pathway to long life for your endoscope.

Fig. 1
A 1.9-mm arthroscope with ( A ) C-mount attachment, ( B ) focusing ring, and ( C ) light source attachment.

Cannulas

The operative system consists of 2 similar cannulas, a trocar and an obturator ( Fig. 2 ). Devices inserted in the cannula, including the scope, need to have a diameter that is at least 0.1 mm smaller than the inner diameter of the cannula. This diameter permits the appropriate ingress and egress of irrigation fluid maintaining joint distention and clarity. By having similar cannulas, instruments and scopes can easily be switched between portals during the procedure. The cannula delivery system facilitates not only use of hand instruments in the joint but also irrigation and maintenance of joint insufflation. Markings on the cannulas begin at 15 mm from the tip and continue in 5-mm increments, allowing the surgeon to monitor depth of penetration. For larger diameter instruments (ie, 2.7 mm) used in more aggressive debridements, the primary author has designed a switch stick facilitating the interchange between the 2.0- and 3.0-mm diameter cannulas.

Fig. 2
Operative system showing cannulas with scoring marks and sharp trocars.

Probes

The straight probe is the most basic arthroscopic hand instrument. It is used for palpation, severing adhesions, and mobilization/temporary immobilization of tissue (ie, disc). The hooked probe is similar to the later except for a small terminal hook. It is the preferred instrument for palpation in cases of chondromalacia. The typical use of this probe is to elevate the anterior aspect of the disc after anterior releasing procedures and to complete the dissection of the disc from the capsule and the pterygoid muscle. The hooked probe is also preferred in difficult cases of disc reduction, with lax/redundant retrodiscal tissue, where a straight probe may lacerate the structure. Hooking of the oblique protuberance before disc reduction enables reduction without herniation of tissue ( Fig. 3 ).

Fig. 3
Hooked and straight probes.

Advanced Armamentarium

Biopsy forceps

The serrated-type forceps have cupped beaks and are used for small biopsy samples and for the debridement of pathologic or fragmented tissues. The basket-type forceps harvest mostly full-thickness biopsy specimens (ie, synovial tissue) ( Fig. 4 ).

Fig. 4
( A ) Cupped biopsy forceps, ( B ) 2.4 suction bunch forceps.

French #5 myringotomy suction tip

This instrument will evacuate clots or heme during arthroscopy. The 2.0-mm cannula easily accommodates this suction.

Meniscus Mender

This packaged set consists of straight and curved spinal needles with a stylet and a suture loop used to snare the suture once passed through the needle. While in the process of designing a less invasive replica of Meniscus Mender I and II (Instrument Makar, Okemos, Michigan), the primary author uses, for most situations, a 22-Ga needle to pass the suture for discopexy procedures ( Fig. 5 ).

Fig. 5
The Meniscus Mender II has a lasso ( top ), an obturator ( center ), and a small-diameter cannula needle ( bottom ).
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

2.4-mm suction punch

The 2.4-mm suction punch is a valuable and efficient instrument when more advanced debridements or partial discectomies are required. It is placed down a 3-mm cannula, and works by cupping and biting the tissue at the distal end. Suction is then applied at the proximal end to withdraw the tissue from the joint and the instrument (see Fig. 4 ).

Other hand instruments

The authors use the bone rasps to smooth bone and curettes to debride clumps of adhesive fibrocartilage of bone surface ( Figs. 6, 7 ) The golden retriever is a valuable magnetized instrument specialized in retrieval of intraarticular broken instruments ( Fig. 8 ).

Fig. 6
Leibinger bone rasps, concave ( left ) and convex ( right ).
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

Fig. 7
Close-up view of Leibinger curette.
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

Fig. 8
A 1.7-mm magnetized golden retriever. It can retrieve broken instruments via the 3.0-mm cannula.
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

Motorized Instruments

The unique concept of motorized shavers and abraders enables suctioning of the arthroscopic field while cutting and removing tissue in an efficient manner. Four factors are paramount for these instruments to function efficiently: (1) the design of the cutting blade, (2) the pressure balance between the suction and the continuous irrigation fluid, (3) the revolution speed (revolutions per minute) of the instrument, and (4) the type of tissue that the surgeon is attempting to cut. The primary author has discovered that the ultimate parameters of efficiency for the shaver are reached at the lower spectrum revolutions per minute–range speed. After developing a refined intraarticular tactile sense for the instrument, the author has noticed that the most efficient shaving occurs with a repeated paw-and-dab motion.

Shavers

The larger of the 2 shavers widely in use, 2.9 mm in diameter, is used for more aggressive arthroscopic arthroplasty. A 2.4-mm diameter suction punch may become necessary with the use of this shaver. For the sake of keeping procedures as minimally invasive as possible, this author has lately only used a 1.9-mm shaver.

Whisker shaver

The one advantage of this shaver is its ability to prevent intraarticular iatrogenic complications. The instrument has been so profiled that the articular surfaces are completely protected from the cutting portion of the active part. The perforations in the external sleeve of the instrument promote a suction effect on the soft tissue that the inner blade cuts next. The whisker shaver has been designed for the debridement of fine fragmented fibrocartilage from articular surfaces, small fibrous adhesions, or small fragments of the disc periphery. It may remove fibrotic or desiccated synovial tissue; however, its use on intact/vascular synovium is discouraged ( Fig. 9 ).

Fig. 9
Close-up of Dyonics whisker shaver (Smith and Nephew, UK) ( left ) and full radius shaver ( right ).
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis: Mosby; 1996; with permission.)

Full radius shaver

Available in 1.9 and 2.9 mm diameter, it is a more aggressive and efficient instrument designed to resect tissue of an even more fibrotic consistency, such as fibrous bands, adhesions, large areas of desiccated synovium, fragmented edges of meniscus, and advanced chondromalacia (see Fig. 9 ).

Abraders

These bone drills (the round and barrel-shaped abraders) only come in 2.9 mm and are used to decorticate the osseous structures and create pinpoint areas of microhemorrhage to promote cartilaginous regeneration ( Fig. 10 ).

Fig. 10
( A ) Close-up of barrel abrader ( left ) and round abrader ( right ). ( B ) Barrel abrader in joint contouring articular surface.
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

Electrosurgery

Electrosurgery is the use of high-frequency electric currents to facilitate a tissue change. The human body’s electrolyte composition makes it a conductor of electricity. During electrocautery, an alternating current is passed to the surgical electrode probe in the form of heat. The manner in which the tissue responds to the electrothermal energy depends on the waveform of the current, the power at the electrode tip, the time of exposure at the electric tip, and the cooling of the tissue with blood circulation. The continuous sinusoidal waveform is used for the cutting mode because it mechanically disrupts cells. The attenuated or dampened waveform, which eventually oscillates down to resting potential, is used for the coagulating mode.

The McCain monopolar and bipolar electrocautery probes (Leibinger, Irving, TX, USA) are fully insulated except at the tips of the instruments. The bipolar probes are by far the most commonly used electrocautery probes. The safer, more rigid probes have the ability to manipulate tissue while delivering the electrical energy. In order not to compromise the insulation of the probes, the recommended settings of the generator should not be exceeded. Although common settings exist for each tip, the individual settings may change based on clinical experience. The introduction and removal of the electrocautery probe in the working cannula is a very deliberate motion. Abrasion of insulation in the process should be avoided at all costs because it can expose another potentially active area away from the tip of the instrument. If this happens, an area of the joint can be iatrogenically injured while outside the arthroscopic field of view. No grounding pad is necessary for bipolar electrocautery, and the irrigation fluid may contain electrolytes. The thousands of arthroscopic procedures performed by this author, including posterior synovial pouch cauterization, electrosurgical anterior release, electrosurgical synovectomy, and electrocautery for hemostasis, have awarded the experience necessary to understand the effects of electrocautery on intraarticular temperature ( Fig. 11 ). The best initial setting for contracture procedures is 15 W and 30 W for coagulation.

Fig. 11
( A ) McCain electrocautery probes. ( B ) Close-up of McCain electrocautery tips. Shown are monopolar sharp hook ( left ) and bipolar blunt ( right ).
( From McCain JP. Principles and practice of temporomandibular joint arthroscopy. St Louis (MO): Mosby; 1996; with permission.)

Monopolar electrocautery is used infrequently. A grounding pad is necessary, and the irrigation fluid must be sterile water, a non–electrolyte-containing solution. The monopolar electrocautery may be used to perform the same procedures more commonly accomplished by bipolar electrocautery.

Laser

Light amplification by stimulated emission of radiation or laser technology transmits energy in the form of a light beam. The laser light beam is collimated and formed of equally spaced and coherent wavelengths. Laser energy is delivered as either a continuous or a pulsated beam of light. The wavelength of a particular laser determines the physical properties of a laser in the clinical use setting.

Holmium YAG laser

This laser’s wavelength is 2140 nm, making it somewhat similar to the CO 2 laser with regard to its high hydro absorbability. The holmium laser, however, has a limited depth of penetration (0.3–0.5 mm), making it very useful intraarticularly. In this author’s hands, this laser variety is the most versatile for arthroscopic techniques on the TMJ, such as anterior release (cutting), synovectomy, posterior scarification, and debridement of fibrocartilage. The small size of the delivery tip facilitates excellent access in limited spaces, whereas its metal encasement prevents the breakage of this quartz fiber. To this date, the holmium YAG laser is considered the most safe and effective modality for intraarticular TMJ delivery of energy. A 0.5-mm holmium laser fiber is secured within a metal hand piece. The diameter of this device is 1.8 mm. The device fits down the 2.0-mm working cannula.

Laser settings for cutting 10 Hz/Reputations 9 W 0.09 J
Laser settings for ablation 8 Hz/Reputations 4 W 0.5 J
Laser settings for contracture 5 Hz/Reputations 2 W 0.40 J

The laser radiation is well absorbed by most biologic tissues, which allows for precise tissue removal. These desirable characteristics suggest a potentially useful arthroscopic tool. In using this laser on patients, both authors have been impressed with the ease and rapidity with which adhesions and fibrillations can be ablated, cartilage sculptured, and rapid coagulation obtained in areas of hemorrhage. In addition, triangulation and manipulation by placing the fiber directly through the skin has not only reduced operating time but has also facilitated more complete removal of adhesions from all areas of the joint compartment, thus, releasing the disc for better function ( Fig. 12 ). Other laser types have not been found to be beneficial in TMJ.

Fig. 12
Introduction of the holmium laser fiber ( blue ) to the joint via cannula.

Radiofrequency Coblation Microdebridement (ArthroCare, USA)

The newest modality for advanced arthroscopy is the radiofrequency (RF) coblation instrumentation. Coblation uses a controlled, non–heat-driven process in which bipolar radiofrequency energy excites the electrodes in a conductive medium, usually saline solution, to create a precisely focused, charged plasma gas. The energized particles in the plasma field have sufficient energy to break the molecular bonds within the tissue, causing the tissue to dissolve or contract at low temperatures (typically 40°C–70°C). Because the RF current does not pass directly through the tissue during the coblation process, tissue heating is minimal. The result is volumetric removal of the target tissue with minimal damage to the surrounding healthy tissue. Coblation technology permits cutting, coagulation, ablation, and contracture ( Fig. 13 ).

RF cutting setting ≥No. 5 (≥200 V)
RF coagulation setting No. 2 (125 V) or default setting for coagulation
RF ablation setting ≥No. 5 (≥200 V)
RF contracture setting No. 2 (125 V)

Fig. 13
Coablation (ArthroCare) probe.

An important technical note for using bipolar or monopolar electrocautery and RF coblation is to monitor the temperature of irrigating fluid as it exits from the cannula so as not to cause thermal damage to surrounding tissue. Also, delivering irrigation in a pulsed, intermittent manner minimizes the risk of overheating the joint.

Armamentarium for advanced TMJ arthroscopy

Basic Armamentarium

Arthroscope

Arthroscopes are available from several suppliers but share similar features. The arthroscope should be less than 2 mm in diameter with an angle of view of 30°. The focal distance should be 0 to infinity. This specification is an absolutely key point because scopes that have focal lengths greater than 1 mm do not permit adequate visualization during advanced arthroscopy ( Fig. 1 ). Other important factors are resolution or sharpness of the image, distortion and flatness of the field, color response, and brightness. The light source should be capable of providing 5000 K color temperature. The arthroscope is a delicate instrument, not to be used in the same manner as a surgical tool. Although the housing is made of materials, such as aluminum and steel, the internal lens components are glass rods, some as small as 1 mm in diameter. A cracked or chipped lens may damage the arthroscope beyond repair. Awareness of the delicacy of the instrument and careful handling is the pathway to long life for your endoscope.

Fig. 1
A 1.9-mm arthroscope with ( A ) C-mount attachment, ( B ) focusing ring, and ( C ) light source attachment.

Cannulas

The operative system consists of 2 similar cannulas, a trocar and an obturator ( Fig. 2 ). Devices inserted in the cannula, including the scope, need to have a diameter that is at least 0.1 mm smaller than the inner diameter of the cannula. This diameter permits the appropriate ingress and egress of irrigation fluid maintaining joint distention and clarity. By having similar cannulas, instruments and scopes can easily be switched between portals during the procedure. The cannula delivery system facilitates not only use of hand instruments in the joint but also irrigation and maintenance of joint insufflation. Markings on the cannulas begin at 15 mm from the tip and continue in 5-mm increments, allowing the surgeon to monitor depth of penetration. For larger diameter instruments (ie, 2.7 mm) used in more aggressive debridements, the primary author has designed a switch stick facilitating the interchange between the 2.0- and 3.0-mm diameter cannulas.

Fig. 2
Operative system showing cannulas with scoring marks and sharp trocars.

Probes

The straight probe is the most basic arthroscopic hand instrument. It is used for palpation, severing adhesions, and mobilization/temporary immobilization of tissue (ie, disc). The hooked probe is similar to the later except for a small terminal hook. It is the preferred instrument for palpation in cases of chondromalacia. The typical use of this probe is to elevate the anterior aspect of the disc after anterior releasing procedures and to complete the dissection of the disc from the capsule and the pterygoid muscle. The hooked probe is also preferred in difficult cases of disc reduction, with lax/redundant retrodiscal tissue, where a straight probe may lacerate the structure. Hooking of the oblique protuberance before disc reduction enables reduction without herniation of tissue ( Fig. 3 ).

Fig. 3
Hooked and straight probes.

Advanced Armamentarium

Biopsy forceps

The serrated-type forceps have cupped beaks and are used for small biopsy samples and for the debridement of pathologic or fragmented tissues. The basket-type forceps harvest mostly full-thickness biopsy specimens (ie, synovial tissue) ( Fig. 4 ).

Fig. 4
( A ) Cupped biopsy forceps, ( B ) 2.4 suction bunch forceps.

French #5 myringotomy suction tip

This instrument will evacuate clots or heme during arthroscopy. The 2.0-mm cannula easily accommodates this suction.

Meniscus Mender

This packaged set consists of straight and curved spinal needles with a stylet and a suture loop used to snare the suture once passed through the needle. While in the process of designing a less invasive replica of Meniscus Mender I and II (Instrument Makar, Okemos, Michigan), the primary author uses, for most situations, a 22-Ga needle to pass the suture for discopexy procedures ( Fig. 5 ).

Jan 23, 2017 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Advanced Arthroscopy of the Temporomandibular Joint
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