EBI^® OsteoGen^TM Surgically Implanted Bone Growth Stimulators

INDICATIONS

EBI OsteoGen Surgically Implantable Bone Growth Stimulators are indicated in the treatment of long bone nonunions. A nonunion is considered to be established when the fracture site shows no visibly progressive signs of healing. Federal Law (U.S.A.) restricts this device to sale by or on the order of a physician. Rx Only - Prescription Only - Single Use Only - Do Not Reuse.

USAGE

OsteoGen 20/S, 20/F*, 20/M, 20/SL* & 20/ML* Stimulators should be used to treat a single nonunion and maintain a cathode current at a constant 20 microamps regardless of changes in bone/tissue resistance over a range of 0-100,000 Ohms.⁵

OsteoGen 40/S, 40/M, 40/SL* & 40/ML* Stimulators are only to be used to treat multiple nonunions or in a severely comminuted nonunion where a single cathode cannot span the entire breadth of the nonunion site. These models must be used with both leads in place, each delivering 20 microamps per lead regardless of changes in bone/tissue resistance over a range of 0-40,000 Ohms.⁵

*OsteoGen Stimulator models currently not available.

CONTRAINDICATIONS

There are no known contraindications to the use of these devices, however, due to insufficient clinical experience, it is not recommended that it be used in the following conditions: pathological fractures due to malignant tumors or in the presence of active osteomyelitis.⁵

WARNINGS

Long-Term Biocompatibility

While titanium has had a clinical history of nearly thirty years of use, long-term effects of implantation in humans are unknown. Titanium does not contain nickel, chromium or cobalt, which have been known to provoke a hypersensitivity response in some patients. "Attempts to produce toxicity in experimental animals have usually failed and the fact that titanium has been used in cosmetic preparations and treatment of skin disorders testifies to its relative innocuousness."⁵

Direct Current in Vivo

Animal studies (in the rat) using capacitively coupled alternating current techniques have shown evidence of excessive bone formation. The significance of these observations in humans is not known. Routine clinical observations extending over a twelve-year period on a limited number of patients treated with the OsteoGen Stimulator has not shown any evidence of excessive bone formation.⁵

Pediatric Nonunions

The safety and effectiveness of using this device in the pediatric population has not been determined. There has not been any lengthening of the leg bones observed using OsteoGen Stimulators. Physicians are advised, however, to monitor these possible effects when using OsteoGen Stimulators and the epiphysis is within the treatment area.⁵

PRECAUTIONS

Electrosurgery

Electrosurgical instruments are capable of producing radio frequency voltages of such magnitude that direct coupling can occur between the cautery tip and lead system of the generator. To preclude the possibility of damage to the generator electronics, electrosurgical equipment should not be used on the patient in the immediate vicinity of the implanted stimulator. If electrosurgery must be done after implantation of the device, leave the electrode/cathode in place so it remains connected and remove the generator, placing it outside of the body with a gloved hand. Only when electrosurgery is completed, place the generator back subcutaneously into the soft tissue.⁵

Diathermy (Microwave, Shortwave or Ultrasonic)

Therapeutic diathermy should not be used in the treatment of a patient who has an OsteoGen Stimulator implanted, since this equipment can also produce voltages which may cause damage to the stimulators’ electronics. Diathermy must never be applied over the site of any bone growth stimulator since high currents induced in the electrode lead can cause burning of the tissues in contact with the cathode (electrode lip).⁵

Handling

The energy source and electronics of the generator are heavily protected within the titanium case and will be unaffected by normal handling. However, the possibility of damage by mechanical shock, such as a drop onto a hard floor, cannot be pre­cluded. Any unit subjected to this type of accident should not be implanted. Out of service or explanted units should be disposed of by industrial garbage disposal. Do not dispose of any unit in an open fire. ⁵

PRECAUTIONS

Use with Internal/External Fixation

When the stimulator is used in conjunction with internal/external metallic fixation devices, caution must be taken to prevent contact with the cathode and the metallic implant. If the cathode comes into contact with the metallic implant, a current dissipation could occur. This reduction of current density could affect the level of therapeutic treatment normally expected. Secondly, if the anode was to come in contact with the metallic implant, possible corrosion or implant failure could occur at the site of contact.⁵

Use of a Second Stimulator

Two or more treatments have been required in up to 3% of the patients reported in the clinical trials. That is, a complete union may not be achieved with the first stimulator, necessitating the implantation of a second stimulator. ⁵

Placement of Generator

Generator should be placed in subcutaneous tissue only. Do not allow generator to touch bone. For optimum patient comfort, the generator should be positioned in an area that is protected from external irritation or impact and unlikely to cause component migration. The generator should be placed 8 - 10 cm away from the cathode. Placement closer than 8 cm may cause build-up of new bone tissue at the proximal end of the cathode at the connector site. The generator should not be implanted more than 4 cm or 1 ½” deep to facilitate removal. The generator should not come into physical contact with internal or external fixation as this may dissipate the therapeutic current and/or significantly impede implant performance.⁵

Placement of Cathodes

The cathode configuration ultimately chosen will be depended upon the anatomical location, surgical approachand technique for the long bone nonunion to be treated.^5,7

For complete prescribing information including contraindications, warnings and precautions, please refer to the EBI OsteoGen Surgically Implantable Both Growth Stimulator manual PN 193102L or visit zimmerbiomet.com/bonehealing.⁵

DESCRIPTION

EBI OsteoGen Surgically Implantable Bone Growth Stimulators are solid state, constant current generators producing a constant direct current. The Stimulators are powered by one lithium battery with a single or dual lead/cathode configuration designed for use in long bone nonunions.⁵  

The electronics and power source are hermetically sealed within a medical grade titanium case, part of which is coated in platinum and acts as the anode (surface area approximately 200 mm²). The straight cathode consists of 25 cm of three-strand titanium wire terminating at one end with a titanium connector socket (OsteoGen 20/S & 20/SL*), or are permanently connected with a fused titanium crimp (OsteoGen 20/F*). The Mesh Cathode consists of two strands of titanium wire woven into a flexible grid with nominal dimensions of 1 x 8 cm, terminating at one end with a titanium connector socket (OsteoGen 20/M & 20/ML*). The single lead configuration consists of 15 cm or 30 cm of drawn brazed stranded stainless steel-silver wire, insulated with silicone and terminating with a titanium connector pin. ⁵  

The OsteoGen 40/S, 40/M, 40/SL* & 40/ML* are solid-state constant current generators producing a constant current of 40 microamps which is divided between two leads of 20 microamps each and powered by one lithium battery. The electronics and power source are also hermetically sealed within a titanium generator case. A circular area on the generator of approximately 400 mm² is platinum coated and functions as the anode. The dual lead configuration for use in multiple long bone nonunion sites consists of 15 cm or 30 cm of drawn brazed stranded stainless steel-silver wire, insulated with silicone and terminating with a titanium connector pin. The dual straight cathodes consist of 25 cm three stranded titanium wire, terminating at each end with a titanium connector socket. Mesh cathodes consist of two strands of titanium wire woven into a flexible grid with nominal dimensions of 1 cm x 8 cm. The dual leads terminating at each end in a titanium connector socket, are connected to the generator. ⁵

MRI

The safety and effectiveness of the stimulators during MRI procedures has not been established. MR imaging at close proximity to implanted devices may be associated with tissue heating, nerve stimulation or movement.⁵

Warning: The MR image of the area close to the generator may be distorted.⁵

FINANCIAL DISCLAIMER

In support of their clinical investigations and/or scientific research, one or more of the authors may have received remuneration from the following: Telectronics, Ltd., BGS Medical Corp., Electro-Biology, Inc. & EBI, L.P.