Authors : Dr. Lanka Mahesh, Dr. Manesh Lahori, Dr.  Lokesh Chandra (Assistant professor, dept. of oral & maxillofacial surgery, kalka dental college, meerut)

Introduction

A sinus-lift procedure is a surgical procedure, performed by an appropriately trained dentist or dental specialist, to augment bone mass in maxilla, which increases the likelihood of successful placement of dental implants. Bone from another part of the body, such as the iliac crest, or artificial bone grafting material is grafted into the bone below the floor of the maxillary sinus. In the upper jaw the amount of bone is reduced by the presence of the sinus. A number of techniques are used to increase the bone height: Onlay grafts, Interpositional (Lefort I) grafts, Inlay grafts for nasal floor, Sinus-lift and grafting.

History

A sinus-lift procedure was first performed by Dr. O.H. Tatum. Jr. Boyne and James were the first to report their 4-year experiences with autogenous grafts placed into the sinus and allowed to heal for 6 months, which was followed by the placement of blade implants. In 1986, Tatum described his techniques for raising the sinus membrane, from a lateral and from an inferior approach.

Surgical techniques

There are several variations of sinus lift procedure, these are the most common:

• Lateral Window approach
  
  - Invented by Tatum in 1986
  

Surgical technic

• A crestal incision is made with vertical extensions and the lateral aspect of the maxilla is exposed.
• Then the osteotomy (anthrostomy) is completed.
• The sinus membrane, Schneiderian Membrane, is then detached from the bony walls of the internal aspects of the sinus, utilizing various curettes.
• Once properly detached, the lateral wall window with the sinus membrane is rotated medially into the sinus.
• The sinus membrane can fold on itself when reflected medially. Implant sites can be prepared and implants placed at this stage.
• The medial part of the sinus is grafted first. The graft material used can be either an autograft, an allograft, a xenograft, an alloplast a growth-factor infused collagen matirx, or combinations thereof.
• After the implants have been placed, the remaining lateral part of the sinus defect is grafted. The flaps are relieved and closed primarily.
• The graft is left for 6–9 months.
• Implant placements should be delayed if they cannot be properly stabilised, to prevent complications.

The Osteotome approach

- Invented by Summer in 1994

Surgical technic

• A crestal incision is made, and the crestal ridge is exposed.
• A sharp osteotome is used to "chisel" a rectangle in the crestal ridge of the maxilla
• Then a sinus-lift osteotome is used like a mallet to fracture the bone, and punch a hole through where the rectangle was created into the sinus floor.
• The sinus is then raised with bone grafting material and implants are placed.

Bone spreader, Bone pusher & bone shaver kit
Pilot drilling till the base of maxillary sinus	creating a greenstick fracture & elevation of schneider’s membrane with convex osteotome
Condensation of augmentation material under the maxillary sinus with bone pusher	Implant insertion

• Hydraulic Sinus Condensing
• invented in 1996, by Dr. Leon Chen
• Unlike the traditional methods of sinus lifts, which typically use an osteotomy of the lateral aspect of the maxilla, the HSC technique uses an osteotomy on the lateral aspect of the crestal ridge of the maxilla.
• The HSC technique has shown to have much shorter recovery times than traditional methods or a bed rest recovery time.

Procedure

A local anesthetic with vasoconstrictor is infiltrated into the gums, and a crestal incision is made. An osteotomy is initiated on the crestal ridge with a 5mm Chen Sinus Bur, or pleizo tip. Drilling ceases about 1mm short of the sinus floor. The surgeon then downsizes to a 2mm sinus bur for the purpose of forming a narrower conical shape at the end of the osteotomy. Constant pressure is applied to the foot pedal of the high speed hand piece to apply hydraulic pressure to the osteotomy while drilling.

While rotating, the 2mm Sinus bur is gently tapped through the cortical bone of the sinus floor, just hard enough form a pinhole through the bone. Hydraulic pressure is introduced to the surgical site at this stage, providing just enough force to begin atraumatically dissecting the membrane from the sinus floor. Once the membrane is loosened, the hydraulic pressure is ceased. The membrane will be at rest, but slightly detached.

The patient is now ready for the initial lifting of the sinus. A bone grafting mixture is then packed through the pinhole and pushed gently against the membrane using a 3mm sinus condenser. This will slightly raise the sinus, resting it on the newly placed bone.

Once the initial lift in complete, the surgeon switches to a regular sized implant drill and bores through the 2mm conical shape. This opens full access to the sinus cavity. The secondary lift introduces more bone graft mixture for the permanent sinus augmentation. The bone grafting material is added until the the sinus has been lifted to the proper height for implant placement.

Once a sufficient amount of bone grafting material is condensed under the membrane, the surgeon will place a dental implant by drilling directly into the newly placed bone grafting material, and placing the implant fixture. The crestal incision is then sutured.

Advantages

Improvement of sinus problems, including:-

• fewer or no headaches,
• Improved breathing,
• Improved drainage
• elimination of sinus pressure.

Innovative implant technology

A minimally invasive procedure which allows for the placements of the implants in the maxillary sinus region The Sinu-LiftTM system is comprised of:

• The Sinu-Drill. This is an intelligent self regulating mechanical hand device that drills the path to the Sinus membrane, disengaging upon contact to avoid rupture.
• The 3mm yellow curette, which is used initially to gently separate the sinus membrane from the bone.
• The 4.2mm blue curette, with a flexible tip,can be used if additional elevation is required.
• A bone packer is provided to helpfill the cavity with bone graft.
• Multifunction handle to help turn wheels & provide additional reach with drill & curettes
• 3.2mm calibrated drill to prepare perforation.

 Surgical Technique

• Identify the location of the Sinus an its anatomy
• Elevate the flap
• Identify correct implant placement and diameter (the Implant Guiding System is shown)
• Use a round bur to mark the desired position of the implant. Use a 2mm drill to prepare the site. Drilling should stop when drill tip is 1-2mm short of the Sinus Membrane.
• Repeat prior step using the precision calibrated 3.2mm Start Drill.
  (If desired, you may use an intermediate sized drill prior to using the calibrated 3.2mm Start Drill)
• Place the Sinu-Drill into the osteotomy and use the white knob to thread the Sinu-drill. The green knob will rotate freely as it is not currently engaged.
• The supplied handle can also be used for additional support and leverage while drilling through the bone.
• The pointed tip of the handle couples with the holes in the Sinu-Drill.
• Continue threading the Sinu-Drill using the white knob while testing the green knob continuously.
• When the green knob engages rotate the Sinu-Drill using the green knob ONLY.
• When you feel the green knob release or rotating freely you have reached the Sinus Membrane without perforation.
• Remove the Sinu-Drill by turning the white knob counter clock-wise.
• You are now ready to begin separating the Sinus Membrane from the bone.
• Use the 3mm yellow curette to gently separate the Sinus Membrane making sure the tip of the curette is in constant contact with the bone (this is a very delicate dissection procedure. Use great caution to avoid membrane rupture).
• The supplied handle can also be used to gain additional support and reach while utilizing the curettes and the bone packer.
• Snap the curette into the open end of the handle.
• If additional elevation is required, utilize the 4.2mm blue curette with a flexible-tip.
• Use the color markings on the curette to verify adequate elevation for desired implant.
• Remove the blue curette.
• Use bone graft to fill in the space created during the procedure.
• Use the bone packer to spread bone graft around the implant site.
• Repeat as necessary.
• If required, use a final drill to increase osteotomy diameter for desired implant.
• Place the treatment planned length and diameter implant and close the flap.

Surgical Drill
The smart Sinu-DrillTM perforates through the bone without rupturing the sinus membrane	Versatile set of flexible curettes help in obtaining the ideal membrane elevation for desired implant
The unique bone packer will easily and accurately allow the placement of bone grafting material	Implant placement

Advantages

• The safest way to lift the sinus membrane. 
• A minimally invasive, non traumatic approach
• Predictable results

 Complications of sinus lift procedure

• Graft failure
• Infection
• Oral antral fistula & sinusitis
• Tilting or loosening of implants
• Cerebritis
• Neurovascular accidents
• Meningitis
• Otitis media
• Brain abscess
• Hemorrhage ( delayed)
• Death ( rare instances)
• Cavernous sinus thrombosis
• Eyelid edema
• Diplopia
• Partial deafness
• Vocal cord disturbances/speech impairment
• Occipital headaches
• Nausea/vomiting
• Nasal bleeding
• Particles of graft in the nose/mouth
• Rare cases altered stability/cochlear imbalance
• Infraorbital nerve paresthesia
• Diagonal vision

References

• Raghoebar GM, Timmenga NM, Reintsema H, Stegenga B, Vissink A. Maxillary bone grafting for insertion of endosseous implants: results after 12-124 months. Clin Oral Implants Res 2001; 12(3): 279-86.
• Chen, Leon, & Cha, Jennifer, An 8-Year Retrospective Study: 1,100 Patients Receiving 1,557 Implants using the Minimally Invasive Hydraulic Sinus Condensing Technique, 'Innovations in Periodontics, Volume 76, Number 3, March, 2005
• Journal of Periodontology March 2005, Vol. 76, No. 3, Pages 482-491