Allis Clamp
Allis clamp with toothed tips. (Image: Wikimedia Commons, public domain.)
An Allis clamp is a ring-handled, ratcheted tissue forceps with several interlocking teeth at its tips. It provides purchase on selected tissue edges, including fascia, skin, vaginal tissue and specimens.[1]
Toothed purchase can injure viable tissue. Tissue quality, the grasp site, pressure, traction and the intended reconstruction determine whether Allis is suitable.
Design
- Jaws. Broad and slightly curved, with several short interlocking teeth at the tip. The teeth are blunt and spread the grasp over a wider footprint than the single point of a tenaculum.
- Lock. Ring handles with a ratcheted box lock. The clamp stays closed without sustained hand pressure.
- Patterns. Tooth arrangement, length and curvature vary by model. Sklar lists a straight 6-inch 3×4-tooth model and a delicate 5-inch 4×5-tooth model; longer patterns are made for deep pelvic and abdominal exposure.[1][2]
| Feature | What it means |
|---|---|
| Several interlocking tip teeth | Distinguishes the common Allis pattern from the single 1×2 tip arrangement of a Kocher. |
| Ratchet | Maintains jaw closure. |
| Different tooth counts and lengths | Choose for access and the tissue bite. |
Uses in reconstructive urology and urogynecology
Allis is described as a moderately atraumatic clamp. In traditional teaching it grips more firmly and injures more than a Babcock and injures less than a Kocher. This ordering comes from convention, not from comparative injury data. It is suited to tissue that will be excised or that tolerates focal trauma.
- Vaginal cuff and flap edges. Vaginal cuff handling in open and vaginal hysterectomy, vesicovaginal and rectovaginal fistula repair, vaginal flap mobilization in sacrocolpopexy, and flap handling in anterior and posterior colporrhaphy.
- Fascia. The edges of a harvested rectus or fascia lata strip for a pubovaginal sling can be tented with Allis clamps to define the cut. Fascial edges can also be held during multilayer closure of large midline or Pfannenstiel incisions.
- Skin edges. Traction during open scrotal, suprapubic, inguinal and perineal dissection.
- Specimens and tracts. A specimen, urachal remnant or small fistula tract is held during excision.
- Mesh. The leading edge of mesh can be held during placement.
- Office cervical stabilization. Allis can substitute for a single-tooth tenaculum (see the evidence below).
Do not use Allis on bowel serosa or ureter that stays in situ, on vessels, or on microsurgical layers. Use a Babcock or a thumb forceps such as the DeBakey. Protect the part of a graft or flap that must stay perfused or form the repair.
Cervical stabilization evidence
A single-blinded randomized trial of 95 IUD insertions reported bleeding after clamp removal in 3 (6.3%) with Allis versus 26 (55.3%) with a single-tooth tenaculum (RR 0.113, 95% CI 0.037 to 0.348). Insertion success, pain scores and the number of hemostatic interventions did not differ. Bleeding was recorded by post-procedure questionnaire, and the trial was registered retrospectively.[3]
Technique and handling
- Grip. Thumb and ring finger through the rings, index finger along the shank.
- Grasp. Place the tips flush against the tissue edge. Many surgeons close to the first or second ratchet tooth. The setting that avoids crush depends on the instrument and the tissue.
- Duration. Release and reposition when the next step allows. Sustained compression injures tissue even with a moderately atraumatic clamp. Avoid repeated grasping of a planned anastomotic or graft edge.
- Slipping. Use the smallest effective bite and traction, and reassess if tissue slips, blanches or tears.
- Inspection. Check tip alignment, the joint and the ratchet before use. Remove a damaged instrument from service.
- Processing. Reprocess the exact instrument according to its instructions. Reusable and disposable versions are not interchangeable.
Comparison with adjacent clamps
| Clamp | Jaw or tip | Usual fit |
|---|---|---|
| Allis | Short interlocking teeth, ratcheted | Skin, fascia, vaginal cuff, tissue bound for resection |
| Babcock | Smooth fenestrated jaws, ratcheted | Bowel, ureter and other hollow structures that remain in situ |
| Kocher | Heavy 1×2 tip teeth, ratcheted | Fascia and discarded tissue needing strong purchase |
| Single-tooth tenaculum | One sharp tooth, ratcheted | Cervical traction |
| DeBakey | Parallel-ridge thumb forceps | Vessels and ureter, handheld |
Historical context
The clamp is named for Oscar Huntington Allis (1836–1921), a Philadelphia surgeon who described a method and instruments for intestinal anastomosis.[4] His name is also attached to the Allis sign, relaxation of the fascia lata between the iliac crest and greater trochanter in femoral neck fracture.
See also: Babcock, Kocher, DeBakey forceps.
References
1. Sklar. Allis tissue forceps, 6 inches, 3×4 teeth, model 36-2060. Manufacturer description and specifications.
2. Sklar. Delicate Allis tissue forceps, 5 inches, 4×5 teeth, model 18-2155. Manufacturer specifications.
3. Andrews B, Quick K, MacLeod E, Edwards K, Rone BK. Cervical bleeding with cervical stabilization during IUD placement: Allis clamp versus single-tooth tenaculum, a randomized control trial. Arch Gynecol Obstet. 2023;307(4):1015–1019. doi:10.1007/s00404-022-06784-x.
4. Allis OH. Classic articles in colonic and rectal surgery. Oscar Huntington Allis 1836-1921. Intestinal anastomosis with suturing of the entire thickness of the intestinal wall. Method and instruments. Dis Colon Rectum. 1986;29(11):776–779. doi:10.1007/bf02555334. PMID 3533473.