Emerging Insights On Minimal Incision Osteotomies

There has been a renaissance in recent years of the once disparaged technique of minimal incision surgery. This author details why minimal incision osteotomies can be advantageous for certain conditions, offers surgical pointers and provides salient advice on overcoming complications.

Unfortunately, there remains a huge stigma with minimally invasive surgery due to some catastrophic results of a small number of unscrupulous surgeons performing minimally invasive surgery of the foot in the United States in the late 1970s and 1980s.

   This is detrimental in my opinion. With the refinement of minimally invasive techniques that has occurred, use of the surgery with proper indications and, most importantly, excellent training, these techniques have greatly improved patient care. Minimal incision surgical techniques also allow for correction of deformities that would otherwise be associated with long postoperative morbidity and, frankly, would be untreatable otherwise.

   Thankfully, due to the refinement and appropriate implementation in Europe by very credible and highly trained surgeons, who have approached this concept with a very judicious and cautious approach, there has been a recent resurgence of this type of surgery in the U.S. There has always been a small faction of podiatric surgeons who have maintained the practice of minimal incision techniques with generally excellent results.

   However, widespread general acceptance professionally has been scant, perhaps because only the few poor outcomes generate acknowledgement. Usually, the only time mainstream foot surgeons would talk about it would be to denigrate the techniques based on complications that surfaced.1-5 There will be more implementation of this type of surgery in the future here. In my opinion, when appropriately trained surgeons perform this method of surgery with technical skill and proper indication, it is a good thing for the patient.

   Currently, there are probably more variations of osteotomies in metatarsals alone than there are conditions of the foot. Indeed, the number alone for osteotomy variations for the correction of hallux valgus would account for most of these. Conceptually, the surgeon as well as the patient must think of an osteotomy as hopefully nothing more than a precise and controlled fracture, one which will position the bone in such a way so healing will result in a correction of the original deformity.

   Until recently, many variations of osteotomy configuration have been solely predicated on the ability for one to apply fixation, primarily internal fixation and usually with screws. A perfect example of this is the Akin osteotomy. While surgeons most often envision external fixation as some type of mini-rail device, simple casting and splinting have withstood centuries of time as effective means to stabilize bone healing after fracture as well as osteotomy.

   However, until recently, with minimally invasive approaches to osteotomies becoming more popular with increased utilization, there has been a wide consensus of opinion that internal fixation is required to attain the optimum result. Some have contended that it is below the standard of care to leave any osteotomy unfixated. This is simply not true in both my experience and given the exposure I have had to large numbers of cases presented in European foot congresses. In many cases, the dissection required to apply fixation results in more morbidity than if it had not been fixated initially. The data and clinical results certainly do not support that contention with our utilization of these techniques. I have also observed this in hundreds of cases I have reviewed in Spain.

   As with any surgical technique or philosophy, there must be implementation with a criteria for proper procedure selection. Without such judiciousness, all techniques can be doomed to failure.6 There are also hybrid situations in which one can perform the osteotomy with a minimally invasive technique and still use fixation (usually all first metatarsals). One can also use a minimally invasive osteotomy simultaneously with other traditional techniques for treating other concurrent pathology, such as in the treatment of lesser metatarsals with concurrent hallux valgus correction. When it comes to discussion of minimally invasive osteotomy techniques, the bone that one is addressing greatly influences whether some type of fixation, other than external taping or splinting, needs to occur. A general rule of thumb is that all first metatarsal osteotomies require fixation.

Pertinent Insights On Bone Healing Principles

Successful bone healing depends on many factors ranging from the metabolic condition of the patient to which bone is involved. Fracture healing is similar to osteotomy healing and the type of fixation can affect outcome. Note that gaps in osteotomies or fractures up to 6 mm can heal physiologically.7

   Any osteotomy that surgeons can perform with the least amount of periosteal disruption is preferable as the periosteum can contribute up to one-third of the blood supply to the bone. This is one considerable aspect that can improve with a minimally invasive osteotomy versus a procedure with large maximal dissection.

   There are essentially three types of fixation: internal (screws, plates, cerclage wiring, etc.); external (casting and splinting in addition to percutaneous K-wires and mini-rail devices); and biologic.

   In minimally invasive osteotomies of the lesser metatarsal, for example, the concept of biologic fixation occurs in addition to the orientation of the osteotomy itself. Due to the minimal amount of dissection and the orientation and position of the osteotomy where there is relatively good alignment in all planes, the undisrupted soft tissues provide support. Additionally, the soft tissues improve blood supply in comparison to where there was maximal dissection required for plating, etc.

Are You Treating The Patient Or The Radiograph?

Conceptually, surgeons love to see postoperative radiographs that show perfect anatomical alignment and demonstrate elaborate screw or plate placement. A 1 mm gap in an otherwise perfect osteotomy can cause surgeon apoplexy but the reality is there is no likelihood of an outcome that is impaired or even less than perfect.

   Frequently the perfect X-ray does exist but this does not always correlate to the surgical outcome. There still may be a lack of full deformity correction, the joint may be stiff and painful, or the foot may still be extremely edematous due to the extent of the surgery. In contradistinction, the X-ray may look horrible, may be considered a complication, and the patient has no sequela and is extremely pleased with the outcome. When beginning to implement minimally invasive osteotomies and techniques into your surgical armamentarium, you will likely need to have a mental readjustment period when it comes to assessing surgical outcomes, particularly when evaluating radiographs.

   You have to treat patients and not X-rays. It is also important to educate your patients about this preoperatively. Bear in mind they may seek a second opinion from someone who has no experience whatsoever with minimally invasive techniques. Such patients will really start criticizing your work when in fact you have done an excellent job. With the normal postoperative healing of bone, the ultimate result will be excellent. Those who have no experience with these techniques cannot judge the outcome of final osteotomy healing by what the X-ray looks like at four weeks post-op.

Rethinking Our Approach To Hammertoe Surgery

In hammertoe correction surgery, it is routine in the U.S. to perform some type of arthroplasty with removal of a portion of the articulation, whether it be the head of the proximal phalanx or a middle phalangectomy. In Europe, whenever possible, the concept is to try to avoid surgical dissection of the articulation during the correction, which decreases postoperative stiffness. Rather, one should implement correction with a minimally invasive osteotomy, either proximal or distal to the joint, in combination with other minimally invasive procedures like tenotomies and capsulotomies.

   In the situation in which there is dorsal displacement of the proximal phalanx on the respective metatarsal head, which has been present for years, there is undoubtedly substantial bony re-adaptation between the base of the proximal phalanx and the head of the metatarsal. It is surgically naïve, in my opinion, to believe that some type of extensive soft tissue procedure (like a flexor tendon transfer) is going to allow for repositioning of the articular deformity present and that the soft tissue correction will be longstanding. If the joint is congruous in its deformed position and there is painless and functional range of motion, why not cut the proximal phalanx distal to the metatarsophalangeal joint (MPJ) and allow for a plantarflexory repositioning of the digit? These heal quickly, do not need fixation except for taping and result in an excellent outcome.

   It is important to note that with this type of hammertoe correction, surgeons are also frequently performing minimal incision osteotomies concurrently and that there will not be a normal grasping motion of the digit post-surgery. An additional benefit of not having internal fixation is that while there is still bone plasticity (up to about three weeks), one can obtain additional correction by blocking the digit and manipulating it into more correction if that is necessary.

Why Minimally Invasive Techniques Can Be Advantageous

There are some forefoot reconstructions that are simply not possible with open techniques. Utilization of percutaneous osteotomies can allow for very satisfactory and functional outcomes with a minimum of trauma. Alternately, with a traditional open technique, so much tissue dissection would be required that the foot would be edematous and non-functional for a long period of time.

   This is especially true for rheumatoid reconstructions. When employing the minimal incision technique, there are the added benefits of less tissue disruption in an immunocompromised patient and a faster return to normal function. However, with central metatarsal osteotomies, my highly trained colleagues in Spain caution that it will take a minimum of three months for them to heal and be non-painful. They almost always recommend doing the second, third and fourth metatarsals concurrently.

   Another very useful indication for a minimally invasive osteotomy is the example of the patient with a failed hallux valgus surgery. There are cases in which patients have had a prior open hallux valgus reconstruction and they are still not happy because the hallux is still (albeit slightly) laterally deviated and touching their second digit. They do not want to go through another lengthy post-op recovery and their first MPJ works well with no pain and a normal range of motion. Another procedure aimed at the level of the first MPJ is certain to result in more stiffness and morbidity.

   A simple percutaneous osteotomy (Akin) of the proximal phalanx works extremely well in this situation. It allows for minimal restriction of activity after surgery and the patient only has to tape/splint the digit for four to six weeks with virtually no postoperative morbidity. There is another advantage to this type of non-fixated osteotomy.

   If the patient desires even more correction after surgery, while there is still plasticity in the bone (up to about three weeks), one can locally anesthetize the digit and manipulate it into better position. This is not possible when one uses rigid internal fixation (see “A Closer Look At The Necessity Of Internal Fixation For Different Osteotomies” below).

Keys To Transitioning Into And Learning Minimally Invasive Techniques

Performing minimally invasive surgery is more difficult and demanding than performing open surgery. There is a steep learning curve for some of these techniques. It would be my recommendation to begin with simple digital work for hammer digit correction and then phase into increased utilization for techniques such as proximal Akin osteotomies. Then one can finally progress to distal metaphyseal work on lesser metatarsals.

   I highly recommend the excellent textbook Minimally Invasive Surgery, which is translated into English for a review of these techniques.8 The anatomical illustrations alone are well worth the cost of the text. As with any surgical procedure, let alone a whole foreign conceptual type of surgery, there are many nuances that one should contemplate before entering into this type of surgery.

   While there is a strong need for the surgeon to be keenly aware of anatomy and topographical location, there is also a strong reliance on the use of intraoperative fluoroscopy to ascertain proper position of the cutting instrument prior to making the osteotomy. Surprisingly, there is very little trauma to surrounding soft tissues with good technique and the use of recommended instrumentation.9

   Special instrumentation is required. For example, you cannot use high-speed rotary instruments as the heat generated will result in a high propensity for thermal bone necrosis. Use low RPM side cutting burrs. For lesser metatarsal osteotomies, we use small, traditional power saws while the assistant applies cooling, sterile water. We have not encountered thermal bone necrosis. This deviates from use of the side cutting burr for lesser metatarsal osteotomies but provides for less of a learning curve and more precision.

   It is beyond the scope of this article to describe detailed surgical techniques. However, with the presentation of a few case examples, hopefully one can gain an appreciation of how powerful these techniques can be with extraordinary surgical outcomes.

How To Revise Failed Hallux Valgus Surgery

Revision surgery for failed hallux valgus correction can be one of the most demanding surgeries the foot surgeon performs. Considerations of revision surgery should include:
1. What does the patient desire?
2. What is really possible?
3. Does the planned revision place the patient at more risk for increased morbidity?

   As we have talked about the perils of treating radiographs and not patients, it is vital to understand what the patient does not like about the outcome. Sometimes, it has almost nothing to do with the original surgery (and almost never involves what the postoperative radiograph looks like). For example, say there is more of a separation between the hallux and second digit. The patient does not like that and wants the second digit corrected.

   A minimally invasive osteotomy may be the ideal correction for this type of revision as there is already significant scar tissue present and often no need to “redo the whole thing.”

   Complex clinodactyly deformity. In a complex fifth digit deformity, the use of a minimally invasive proximal phalangeal base osteotomy provides ultimate correction of this complex deformity with minimal postoperative morbidity and often little, if any, post-op pain.

   Diffuse metatarsalgia. Metatarsalgia is a common forefoot condition that can be difficult to treat and one must always evaluate whether an equinus condition exists concomitantly. If there is overwhelming gastrocnemius equinus, it is my opinion that one address this component primarily. This approach has much less postoperative morbidity than forefoot metatarsal osteotomies.10 Research has found the Weil osteotomy to be particularly beneficial to treat this condition and it is well suited to minimally invasive techniques.11

   Additionally, when it comes to high-risk patients with ulceration, studies have found minimally invasive osteotomies to be beneficial with a high level of efficacy and low complication rate.12,13 This may allow for intervention that open techniques would preclude.

How To Address Any Complications That Arise

As with any surgical technique, there will be complications. Fortunately, in my experience, they have been small and rare. I believe that most complications emanate from two things: inappropriate indication of the technique and failure somewhere in the postoperative course.

   With this type of surgery, my worst complication has been a delayed healing of three lesser metatarsal osteotomies in which the patient was feeling so well that she decided to start playing golf at six weeks post-op. Naturally, there was a long period of immobilization and bone stimulation with ultimate healing. Rarely will a lesser metatarsal osteotomy at the distal metaphyseal not heal if one gives it enough time. Another potential complication is an extrusion of bone paste postoperatively if one does not adequately remove it at the time of surgery.

In Summary

The use of minimally invasive osteotomies provides the surgeon with some very powerful techniques. These techniques can provide previously unattainable corrections of very complex and severe forefoot deformity. However, it is important to emphasize that these techniques require advanced training and gradual implementation.

   Dr. Barrett is an Adjunct Professor within the Arizona Podiatric Medicine Program at the Midwestern University College of Health Sciences. He is a Fellow of the American College of Foot and Ankle Surgeons.

References
1. Portaluri M. Hallux valgus correction by the method of Bosch: a clinical evaluation. Foot Ankle Clin. 2000; 5(3):499-511, vi.
2. Legenstein R, Bonomo J, Huber W, Boesch P. Correction of tailor’s bunion with the Boesch technique: a retrospective study. Foot Ankle Int. 2007; 28(7):799-803.
3. Henry J, Besse JL, Fessy MH. Distal osteotomy of the lateral metatarsals: a series of 72 cases comparing the Weil osteotomy and the DMMO percutaneous osteotomy. Orthop Traumatol Surg Res. 2011; 97(6 Suppl):S57-65.
4. Giannini S, Faldini C, Vannini F, Digennaro V, Bevoni R, Luciani D. The minimally invasive osteotomy “S.E.R.I.” (simple, effective, rapid, inexpensive) for correction of bunionette deformity. Foot Ankle Int. 2008; 29(3):282-286.
5. Bauer T, de Lavigne C, Biau D, De Prado M, Isham S, Laffenetre O. Percutaneous hallux valgus surgery: a prospective multicenter study of 189 cases. Orthop Clin North Am. 2009; 40(4):505-514, ix.
6. Waizy H, Olender G, Mansouri F, Floerkemeier T, Stukenborg-Colsman C. Minimally invasive osteotomy for symptomatic bunionette deformity is not advisable for severe deformities: a critical retrospective analysis of the results. Foot Ankle Spec. 2012; 5(2):91-96.
7. Banks AS, Downey MS, Martin DE, Miller SJ, eds. McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, third edition. Chapter 4. Lippincott, Williams and Wilkins, Philadelphia, 2001, p. 68.
8. DePrado M, Golano P, Ripoli LR. Minimally invasive foot surgery: surgical techniques, indications, anatomical basis. About Your Health, 2009.
9. DiDomenico LA, Anain J, Wargo-Dorsey M. Assessment of medial and lateral neurovascular structures after percutaneous posterior calcaneal displacement osteotomy: a cadaver study. J Foot Ankle Surg. 2011; 50(6):668-671.
10. Saxena A, Gollwitzer H, Widtfeldt A, DiDomenico LA. [Endoscopic gastrocnemius recession as therapy for gastrocnemius equinus]. Z Orthop Unfall. 2007; 145(4):499-504.
11. Schuh R, Trnka HJ. Metatarsalgia: distal metatarsal osteotomies. Foot Ankle Clin. 2011; 16(4):583-595.
12. Roukis TS, Schade VL. Minimum-incision metatarsal osteotomies. Clin Podiatr Med Surg. 2008; 25(4):587-607, viii.
13. Roukis TS. Central metatarsal head-neck osteotomies: indications and operative techniques. Clin Podiatr Med Surg. 2005; 22(2):197-222, vi.

   Editor’s note: For further reading, see Dr. Barrett’s DPM Blog “Reconsidering Foreign Advances In Minimally Invasive Surgery” at https://bit.ly/cnLpAc or “Minimal Incision Surgery: Can It Have An Impact In Diabetic Limb Salvage?” in the March 2009 issue of Podiatry Today.