Steinmann Pin Repulsion of Fractured 307

This 9 year old mare has a fractured 307 with part of the buccal crown missing and displacement of the lingual portion. Feed was packing into the fractured area and deep into the periodontal space. Radiographs revealed a distorted, blunted root with small root-like projections on the distal caudal portion of the fractured 307.

Oral extraction is the treatment of choice, which was attempted but was not successful.Several tooth fragments were removed but the distorted root could not be extracted. The horse was prepped for surgical repulsion.

A 16 gauge needle was inserted in the proposed surgical site under the 307 and then radiographed to determine the exact location of entry for repulsion. It is necessary for the placement of the stieman to be directly in the middle of the root fragment for successful repulsion. The horse was sedated and the inferior alveolar nerve was blocked. This nerve block desensitizes all of the teeth and immediate surrounding structures only. Lidocaine was infused into the cheek and distal mandible in the area of the 307 to complete the nerve block for this standing procedure. A small biopsy punch was used to remove the skin and under lying tissue, including the periosteum. An 1/8th inch stieman pin with a trocar point was tapped through the distal mandible at the exact location under the 307 with a surgical mallet. A full mouth speculum is used to open the mouth to allow an assistant to place a finger on the root fragment while the stieman pin is advance to confirm proper positioning of the pin and to communicate with the surgeon concerning movement of the fragment during the procedure. Once the pin contacts the center of the fragment, a vibration will be noted by the assistant as the pin is tapped. In this case, the tooth root was repulsed intact without any portion of the root being fractured during the procedure. Post radiographs were taken to confirm complete extraction of the tooth.

The alveolus was flushed with diluted chlorhexidine solution after repulsion. Furacin powder was packed in alveolus and left to dissolve. The owner was instructed to feed only soft feeds for two weeks and flush the mouth out daily with large quantities of water using a garden hose placed in the interdental space. The horse was given tetanus toxoid, 500mg of Flunixin Meglumne, and dispensed Trimethroprim and Sulfadazine B.I.D. for 10 days.

Discussion:

Extractions of equine cheek teeth can be difficult and every case is unique. There are several different extraction techniques that may be employed and choosing the correct technique will depend on the clinical exam, radiographic findings, age of horse, anatomical location of tooth, and economics. Oral extraction is economical and the least traumatic procedure which can be accomplished in the standing horse with sedation and local anesthesia. However, this technique is not always successful and surgical methods may be required to complete the extraction. In this case, a small Steinmann Pin was used which has several advantages. The pin is small and strong enough to penetrate the mandible with out disruption of the vessels in the mandibular canal distal to the root. Careful advancement of the trocar point at the level of the canal usually slides past the major vessel thus reducing trauma and hemorrhage. The resulting hole in the mandible is very small, heals quickly, and is cosmetically acceptable. Instrumentation for this procedure is simple, available , and economical. This method of extraction can be accomplished on a standing horse with sedation and effective nerve blocks.
B.W. Fletcher, DVM

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