MIS Bunion Surgery Notes

Introduction

  • Dr. Wigley discusses minimally invasive bunion surgery (MIS Bunion).

About Dr. Wigley

  • Born and raised in Memphis, Tennessee.
  • Undergrad at Dillard University in New Orleans.
  • Went to Barry University in South Florida.
  • Completed surgical residency at Palmetto General Hospital.
  • Private practice focusing on rear foot, forefoot, soft tissue mass, and wound care initially.
  • Found a niche in minimally invasive bunion surgery in South Florida.

Overview of MIS Bunion

  • The talk will cover the techniques, benefits, and outcomes of the Minnow Vasor Bunion procedure.
  • It's an introductory overview for various skill levels.

Bunion Overview (Hallux Valgus)

  • Number one foot deformity globally.
  • Involves the big toe shifting towards the second digit.
  • Causes discomfort, pain, and swelling, especially with certain shoes.
  • Fixation techniques vary from no fixation to screws.
  • The goal is to perfect bunion correction, with minimally invasive approaches being preferred due to less downtime and smaller scars.

Hallux Valgus Details

  • Common deformity of the big toe joint.
  • Symptoms include pain, redness, swelling, and shoe-wearing difficulties.
  • Causes often include genetics, improper footwear, and inflammatory conditions such as arthritis.

Traditional Bunionectomy vs. Minimally Invasive Surgery

  • Dr. Wigley has moved away from traditional open incisions for about 95% of bunion cases.
  • Recovery Time: MIS allows patients to return to comfortable shoe gear in 3-4 weeks versus 6-8 weeks with traditional methods.
  • Scarring: MIS results in smaller, less visible scars, which is a significant concern for patients in South Florida.
  • The primary goal of surgery is to alleviate pain and improve mobility.
  • Surgical correction is considered the only effective method for bunion correction.
  • Dr. Wigley has performed over 400 bunion surgeries in 11 years.

Patient Experiences with Traditional Procedures

  • Persistent swelling lasting almost a year.
  • Failed recovery periods.
  • Long healing times that restrict activity.
  • Reluctance to undergo surgery on the other foot in bilateral cases.

Minimally Invasive Approach Details

  • Incision Size: Very small incisions (1-2 millimeters) compared to 4-6 inches with traditional methods.
  • Tool Used: 2.2 Shannon burr.
  • Cosmetic Outcome: Improved due to minimal scarring.
  • Trauma: Less tissue disruption, involving only micro-invasive techniques.
  • Recovery: Faster recovery times due to reduced tissue trauma.

MIS Benefits

  • Smaller incision reduces tissue trauma, allowing for quicker recovery.
  • Patients appreciate faster recovery, often scheduling surgery before holidays for extended recovery time.
  • Most patients can return to some type of shoe gear within 21-28 days.

Indications for MIS

  • Mild to moderate bunions.
  • Early-stage bunions without significant disease progression.
  • MIS can stabilize hypermobile first rays by shifting the metatarsal component to a desired position.
  • Realistic patient expectations and commitment to postoperative protocol are essential.

Surgical Techniques

  • Patient Positioning: Supine with foot hanging off the bed to allow use of mini C-arm or C-arm apparatus without obstructions.
  • Bur Osteotomy: Using a 2.2 Shannon burr.
  • First Metatarsal Surgery: Placing surgery in the medullary canal to shift about 90% of the metatarsal head for correction.
  • Fixation: Moving from K-wires to cortical and cancellous screws for compression, transversing the base of the first metatarsal towards the lateral sesamoid.
  • The choice of fixation method depends on surgeon preference.

Postoperative Period

  • Immediate weight-bearing on the third day with a postoperative shoe is common.
  • Micromotion aids bone callus formation and reduces swelling.
  • Less swelling reduces complications.
  • The choice between a surgical boot and a cam walker depends on patient compliance.
  • Proper wound care and weekly check-ups for the first 3-4 weeks, followed by a final follow-up at week 6 or 7.
  • Transition to normal tennis shoes for comfort around week four, with expected dorsiflexion of the first metatarsal.

Case Examples

  • Example of minimally invasive surgery correcting a moderate bunion (22-26 degrees) to a near-zero degree intermetatarsal angle.
  • Early career techniques involved landing two parallel screws.
  • Incision healed in about two weeks with minimal swelling.

Recapping Benefits of MIS

  • Pain reduction
  • Faster recovery time
  • High patient satisfaction leading to referrals
  • Cosmetically appealing results due to invisible scars can cause jealousy among those with traditional bunionectomy scars

Outcomes

  • Evidence based on randomized control studies, retrospective analyses, and meta-analyses, with studies being relatively recent (within the last seven years).
  • Dr. Wigley uses MIS for 90-95% of bunion surgeries due to the demographics he serves.

Overcoming the Learning Curve

  • Mastery requires dedicated training and practice.
  • Practicing dexterity using blocks to perfect cuts can be beneficial.
  • Fluoroscopy is essential for precision, with a skilled technician being crucial.

Personal Methods

  • Landing two screws parallel to each other, aiming for the lateral sesamoid.
  • Achieving nearly 100% shifts.
  • Patients are very satisfied with the outcomes.

Q&A Section

  • Screw Diameters and Lengths:
    • Shooting from the base of the first metatarsal to the lateral sesamoid:
      • 54mm54 \text{mm} screw from the base of the first with % correction to the lateral sesamoid.
      • For a traditional two-screw technique, use 44 mm to 36 mm screws depending on the parallel offset.
      • Lateral screw is usually 44mm44 \text{mm}, with a 4mm4 \text{mm} to 6mm6 \text{mm} decrease from the medial screw.
    • Using a 4.04.0 diameter on nearly all screws, rarely using a 3.03.0.
  • Cost Difference (Open vs. MIS):
    • MIS uses fewer instruments and materials.
    • Savings come from the time spent in the operating room; shorter procedures reduce costs for anesthesia and supplies.
  • Patient Selection for MIS:
    • Surgeon discretion is key based on patient compliance and underlying mental elements.
    • Comorbidities, psychiatric clearances, and potential non-adherence to instructions must be considered.
  • Intermetatarsal Angle Cut Off:
    • Up until recently, anything in Lapidus territory was a cutoff, requiring a first metatarsal uniform fusion.
    • Now, Dr. Wigley is using a % shift to unlock severe metatarsal joints, avoiding the need for fusion.
  • Compression in MIS Implants:
    • There's no definitive evidence between compression versus non-compressive implants.
    • AccuTrack screws have a conical depression, allowing for necessary correction that Herbert screws don't, which can lead to blowouts.
  • Tool for Pushing Capital Fragment Laterally:
    • Freehand freer down the metrical canal for leverage.
    • Mosquito hemostat down the medullary canal for shifting.
  • Frequency of Aiken Alongside Lateral Osteotomy:
    • Around 15%15 \%. Releasing the lateral capsule shifts the toe enough to avoid needing an Aiken.
  • Jig System Recommendation for Young Surgeons:
    • Yes, to take advantage of readily available technology.
  • Learning Curve for Freehand MIS:
    • Around the seventh or eighth procedure, one gains a better feel for the technique.
  • Rep Advice for Switching from Herbert to Accutrack Screws:
    • Highlight the need for a smaller incision with Accutrack.
    • Point out the potential for wall blowout with Herbert screws.
    • Emphasize that Accutrack’s conical shape decreases stress rising and blowback.
  • Opinion on 3D Printed Patient-Specific Devices
    • Cost is a factor relative to time and patient population.
  • Use of Parallel Wire Guide
    • There's a place for them. It's not slim enough right now.
  • Final Thoughts:
    • Be fearless and embrace the MIS world.
    • It is stable and results in fewer headaches long term.