SURGICAL TECHNIQUE
Forearm Transplantation Osteosynthesis Using Modified Ulnar Shortening Osteotomy Technique James P. Higgins, MD, Jaimie T. Shores, MD, Ryan D. Katz, MD, W. P. Andrew Lee, MD, Bruce S. Wolock, MD
Surgical Technique
One of the challenges of forearm-level hand transplantation surgery is the achievement of osseous union of the ulna given the substantial soft tissue dissection, the use of immune modulating medications, and the diaphyseal level of osseous coaptation. Modification of the conventional surgical technique for an elective ulnar shortening osteotomy provides the advantages of precise osteotomy alignment, a large contact surface oblique osteotomy, and lag screw and compression plating technique. A step-by-step description of the developed modification is provided with a case example. (J Hand Surg Am. 2014;39(1):134e142. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Key words Hand transplantation, ulnar shortening osteotomy, ulnar nonunion, compression plating.
O
of upper extremity allotransplantation is the application of conventional hand surgical techniques to the unique requirements of coapting tissue from donor to recipient. Upon first glance, forearm-level transplantation may seem to pose the same challenges of the more familiar craft of replantation. However, muscle, nerve, and bone coaptation need not occur at the level of the amputation stump because more tissue is available than is needed. Muscle coaptation, for example, may be purposefully performed at the muscles’ origins to preserve entire musculotendinous units, whereas nerve coaptation may be planned as distally as possible to minimize the period of reinnervation. Coaptation of the osseous elements is likewise different from replantation.1,2 NE OF THE MANY CHALLENGES
From the Curtis National Hand Center, MedStar Union Memorial Hospital; and the Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Received for publication June 12, 2013; accepted in revised form October 16, 2013. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: James P. Higgins, MD, care of Anne Mattson, the Curtis National Hand Center, MedStar Union Memorial Hospital, 3333 North Calvert Street, Mezzanine, Baltimore, MD 21218; e-mail: [email protected]. 0363-5023/14/3901-0026$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2013.10.005
134
r
Ó 2014 ASSH
r
Published by Elsevier, Inc. All rights reserved.
Osseous coaptation may be planned as distally as possible while permitting resection of poor-quality bone from the amputation stump. Additional resection is avoided to preserve length of the stump in the unfortunate setting of loss of the transplanted part.1,2 In addition, a hybrid osteosynthesis is created by similarly, but not identically, sized skeletal structures. This may permit the alignment of only 1 cortical surface during plating and yield a marked difference in the respective interosseous intervals proximal and distal to the site of osteosynthesis. Whether the osteosynthesis is diaphyseal, metadiaphyseal, or metaphyseal, concern for osseous nonunion (particularly ulnar) after transplantation exists because of the required concomitant use of immune modulating medications3e5 and the relatively large area of surgical exposure or dissection. (Shores JT. ASRT Update: complications to date— the bad and the ugly [hand transplantation]. Presented at the annual scientific meeting of the American Society for Reconstructive Microsurgery, Las Vegas, NV, 2012.) Conventional transverse osteotomy compression plating technique presents technical challenges. The transverse osteotomy provides minimal surface area for coaptation. The creation of exacting transverse, oblique, or step-cut osteotomies with freehand use of bone saws may be imprecise, particularly with the potentially diverse morphology of the donor and
MODIFIED USO PLATING IN HAND TRANSPLANTATION
135
3 bicortical screws on both sides of the osteotomy with an additional precise 3.2-mm oblique lag screw. Other commercial USO systems we evaluated did not offer all of these attributes.
recipient ulnar components. Our team sought to minimize the potential for imprecision, maximize the area of contact, and achieve maximal compression. This goal was sought with great value placed on speed and reproducibility because this would be performed before reperfusion of the transplanted part. Elective ulnar shortening osteotomy (USO) has evolved in the use of commercially available implants that enable the surgeon to rapidly and reproducibly create precise oblique osteotomies to maximize the contact area for osteosynthesis and achieve both dynamic and lag screw compression. The limited studies available on these devices demonstrate outstanding success.6,7 Only 1 retrospective study favorably compared nonunion rates using 1 such device (0 of 52 cases) with freehand osteotomy and compression plating (3 of 45 cases), but failed to demonstrate statistical significance.8 To ensure greatest precision, USO implants are designed to achieve fixation on both sides of the proposed shortening site before osteotomy. Modification of this technique is required to enable its application to the separate and often dissimilar donor and recipient ulnae. A stepwise description of this modification is provided.
Forearm transplant USO technique The TriMed USO system provides 1 universal plate that is used for both right and left arms. The direction of the lag screw is determined by whether it is a right or left arm and whether the plate is positioned volarly or dorsally. The plate is put on volarly on the left arm (and dorsally on the right) at the proximal forearm stump. This enables the drill guide to be attached over the subcutaneous surface of the ulna. This orientation also ensures that the sliding hole is on the distal (donor) part, and the lag screw trajectory is from proximal to distal (Fig. 1). The plate is attached to the proximal (recipient) ulna, first taking care to make sure that it is aligned with the long axis of the ulna. All 3 proximal screws should be placed, leaving the lag screw hole open (and anticipating the lag screw being directed from proximal to distal). This can be performed by the recipient limb preparation team before receiving the prepared donor arm.
TECHNIQUE Implant selection Forearm-level osteosynthesis normally mandates the use of conventional 3.5-mm compression plating. We selected the TriMed USO system (TriMed, Inc., Santa Clarita, CA) because it closely approximates the strength and caliber of conventional forearm plating. Favorable characteristics included its stout stainless-steel design and composition, its use of 3.2-mm screws throughout, and its ability to obtain
Step 1: The plate is placed volarly on the left recipient ulna (dorsally on a right forearm transplant) with 3 screws in the proximal end of the plate, leaving the obliquely oriented lag screw hole proximal (directed distally). The “B” angled saw guide is then used to cut the ulna with an oblique osteotomy. This is performed as distally as possible so that only the minimal amount of bone will be lost in an effort to obtain an oblique osteotomy. The plate is left in place on the proximal stump (Fig. 2).
J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
FIGURE 1: Representation of prepared left forearm-level recipient amputation stump with volar positioned plate directing lag screw hole in a distal trajectory. Ulna is shown with unprepared transverse bone amputation.
136
MODIFIED USO PLATING IN HAND TRANSPLANTATION
Surgical Technique FIGURE 2: Representation of “B” saw guide affixed to side of plate to enable creation of precise oblique osteotomy. Inset demonstrates the position of the saw guide to require minimal bone resection while achieving desired angled osteotomy.
Step 2: The donor arm is brought into the field after preparation by the donor forearm team (described subsequently). The donor arm has previously been prepared with a transverse osteotomy. The donor ulna is placed against the plate, clamping it distally so that it is aligned with the proximal ulna (Fig. 3). The osteotomy is then freehand-revised to be oblique and parallel to the proximal stump osteotomy. The intervening triangular bone segment is removed (Fig. 4). After releasing the clamp on the distal part, the 2 segments are brought into close opposition and the clamps are replaced securing the distal part to the plate. The slotted-hole screw is inserted as far away from the osteotomy as possible to hold the approximation of the distal plate. This slotted screw and a bone clamp (around the plate and the distal ulna) are used to hold longitudinal alignment (Fig. 5). Step 3: A 5-mm resection “A” saw guide is attached to the plate. A sagittal saw is used through the guide to resect 5 mm on the distal piece. This 5-mm resection J Hand Surg Am.
should ensure complete correction of any lack of parallel alignment of the previous freehanded osteotomy (Fig. 6). The TriMed compression clamp is then applied. There is only 1 way that the clamp can be applied, so inappropriate application is not possible. One talon of this device inserts into the only hole in the edge of the plate that will accommodate it. The other talon of the clamp is cannulated. A K-wire should be driven through the cannulated clamp sleeve into the subcutaneous surface of the ulna, dorsal to the midaxis of the bone (volar to the midaxis of the ulna if the plate is applied dorsally on a right arm transplant). This position enables the clamp to prevent the distal ulna from migrating off the plate when compression is applied to the osteotomy (Fig. 7). The sliding screw should then be loosened a quarter turn. Compression is applied with the clamp. The oblique lag screw guide is then mounted onto the plate. The authors have found it helpful to secure the lag screw drill guide and the compressed r
Vol. 39, January 2014
137
FIGURE 3: A Cadaver model demonstrating placement of the donor arm abutting the prepared recipient angled osteotomy. The clamp is applied for longitudinal alignment and stability. B Magnified view of placement.
FIGURE 4: Cadaver model demonstrating the freehand performed roughly parallel osteotomy made in the donor ulna. The clamp maintains longitudinal alignment and stability.
in the standard fashion. The K-wire and compression clamp may then be removed (Fig. 9). Step 5: Attention is then directed to the radius. Ideally, there should be approximately 2 cm overlap between the 2 radii at this point (Fig. 10A). The donor arm has had 2 transverse Kwires placed across the interosseous membrane (IOM) just proximal to the distal radioulnar joint to maintain neutral rotation and native ulnar variance (described subsequently). With the 2 radii overlapping, a freehand transverse sagittal
osteotomy site with a bone clamp applied, as shown in Fig. 8. Step 4: The lag screw hole is drilled using the mounted drill guide. All screws are 3.2 and all use the same size drill (including the lag screw, which is partially threaded and thus does not need a larger proximal drill hole). The lag screw is measured and firmly applied. The plate now has all 4 proximal screws in place. The distal sliding-hole screw is tightened and then the remaining 2 bicortical screws in the distal segment are applied J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
138
MODIFIED USO PLATING IN HAND TRANSPLANTATION
FIGURE 5: Cadaver model demonstrating approximations of the roughly parallel osteotomies. A screw is placed in the distal-most position in the slotted screw hole, providing longitudinal alignment and stability of the distal segment with the clamp.
Surgical Technique FIGURE 6: Representation of 5-mm “A” saw guide affixed to side of plate to enable creation of precise oblique osteotomy in the distal bone segment to mimic the proximal osteotomy. Inset demonstrates the position of the saw guide and the correction of the less precise previous freehand osteotomy.
With the parallel alignment of the osteotomies perfected, attention is turned to rotational alignment. The IOM emanates from the medial aspect of the radius at the acute interosseous ridge that provides a landmark for rotational alignment. At this point in the procedure, the ulna has been fixed securely and the
saw osteotomy is performed. The initial cut can be made purposefully, resulting in 1 to 2 mm of overlap. This enables the surgeon to assess the quality and parallel alignment of the initial osteotomy. If it is inaccurate, it may then be improved with a more parallel subsequent cut. J Hand Surg Am.
r
Vol. 39, January 2014
139
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
FIGURE 7: Representation of the compression clamp affixed to side of the plate to enable closure of the 5-mm gap after slight loosening of the slotted-hole screw and distal clamp.
could be measured preoperatively on the patient’s native contralateral forearm x-ray from olecranon to ulnar styloid. In cases of bilateral transplantation where the contralateral transplantation is also at forearm level, the desired length can be estimated preoperatively based on both the donor and recipient skeletal dimensions, considering the advantages of shorter total forearm length on nerve and tendon coaptation. Finally, in a case of bilateral transplantation in which the contralateral side is performed above-elbow; the ideal total length of the operative ulna will be determined by x-ray measurements of the donor ulna. This desired ulnar length should be communicated to the teams working on both the donor and recipient operative tables. The donor team should affix the forearm in neutral rotation with provisional intraoperative K-wires driven across the IOM proximal to the distal radioulnar joint. This will ensure neutral forearm rotation, preservation of the donor’s native
distal portion of the radius is held in neutral rotation to the distal ulna by the provisional K-wires. It is still possible, however, to neglect proper rotation because the proximal radius is free to rotate. Taking care to align pronosupination, the radius may be plated volarly in compression with a stainless-steel, 3.5-mm dynamic compression plate. It is logical to affix the plate on the radius proximally first, then drill a distal hole in compression mode (Fig. 10B). Next the K-wires holding rotation and variance are removed to permit dynamic compression. Finally, dynamic screw compression is obtained in the drilled hole. The remaining distal holes can be used for bicortical screw fixation in the standard fashion (Fig. 10C). Achieving appropriate forearm length The desired total length of the operative ulna is dictated by a measured length of the patient’s opposite ulna. In the setting of unilateral transplantation, this J Hand Surg Am.
r
Vol. 39, January 2014
140
MODIFIED USO PLATING IN HAND TRANSPLANTATION
Surgical Technique FIGURE 8: Representation of the instrumentation configuration after compression of the osteosynthesis site and lag screw guide application for precise drilling across the osteotomy.
FIGURE 9: Cadaver model demonstrating precise alignment and compression of the oblique osteotomy. Note the different size and morphology of the donor and recipient ulnae.
ulnar variance, and appropriate native tension of the donor’s IOM/distal radioulnar joint alignment before destabilizing the forearm axis. The donor team should await length calculations from the recipient team before performing osteotomies. J Hand Surg Am.
After the recipient team resects the forearm stump back to good-quality bone, the recipient team should perform the oblique plate and guidee directed osteotomy (described in step 1 above). The recipient team should the measure the distance from r
Vol. 39, January 2014
141
FIGURE 10: Cadaver model demonstrating A overlap of the 2 radii after completion of ulnar fixation. B After careful transverse osteotomy of the radii, the 3.5-mm compression plate is affixed volarly on the proximal radius first. Note that the distal radioulnar joint (DRUJ) is held at native length and in neutral rotation by 2 transverse provisional K-wires across the DRUJ of the donor part. C After drilling the first distal hole in compression mode, the DRUJ K-wires are removed and conventional compression plating technique is used to complete fixation in neutral rotation.
FIGURE 11: A Preoperative lateral and B anteroposterior radiographs of a forearm-level transplant recipient’s left arm. C Postoperative radiographs of same patient 4 months after transplantation, demonstrating osteosynthesis of both radius and ulna. The ulna progressed faster and demonstrates greater callus formation.
J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
142
MODIFIED USO PLATING IN HAND TRANSPLANTATION
have not been reported to determine the prevalence or associated factors influencing ulnar healing. The procedure described here was developed to improve on the surgical technique to minimize risk of ulnar nonunion. Although the precision and compression achievable with USO plating technique for the ulna are desirable, consideration must be given to the complexity of the technique and its potential to lengthen operative time. We have found that meticulous rehearsal and team coordination have limited the osteosynthesis time to approximately 30 minutes. This accounts for osteotomy, fixation, and compression of the ulna. Operative times of 60 minutes for elective ulna shortening osteotomies are reported in the literature using this system and measuring time from skin incision to suture closure.6 Our osteosynthesis time excludes soft tissue exposure and closure because these are performed extensively during other portions of the larger transplant operation.
the recipient olecranon to the tip of remaining stump. The following calculation should be made: Desired total ulnar length Prepared recipient stump length þ 2 cm ¼ Length of donor ulna from styloid to transverse osteotomy
Surgical Technique
This measurement will be communicated back to the donor team so they can plan their ulnar osteotomy. The bone loss of length from the oblique osteotomy should be equal to the thickness of the ulna (because the resection is a triangle with 2 equal sides at 90 ). Ulnar thickness, and thus resection length, can be estimated at 16 mm. This is then added to the additional bone loss from the 5-mm precise resection made with the 5-mm “A” saw guide (see above). This should result in a final length of the operative ulna within a few millimeters of the desired length (as determined above). The donor forearm team should perform the radius osteotomy approximately 2 cm proximal to the precisely measured ulnar osteotomy. The recipient team will plan on having the radius stump equal to or longer than the precisely measured ulnar osteotomy. This will leave the overlap of the radii in the 2- to 4-cm range for correction after the completion of ulnar fixation.
DISCUSSION After significant planning and rehearsal, the use of a USO plating technique described above can maximize the osteosynthesis contact area with a precise oblique osteotomy and achieve reliable, rapid, and reproducible lag and dynamic screw compression to minimize the risk of ulnar nonunion (Fig. 11). The technique also provides a method for achieving the calculated ulnar length desired after transplantation.
COMPLICATIONS Forearm-level transplantation osteosynthesis technique poses challenges unlike those routinely encountered with forearm fractures or forearm replantation. These challenges result from the availability of excess bone, dissimilar morphology of donor and recipient bones and interosseous intervals, lack of landmarks for length determination, and use of postoperative immune-modulating medications. We have experienced a higher than anticipated rate of nonunion of the ulna in cases of forearm-level allotransplantation (3 ulnar nonunions in 2 patients who required surgical intervention; 2 progressed to union and the other required a Darrach resection) (Shores JT. ASRT Update: Complications to date—the bad and the ugly [hand transplantation]. Presented at the annual scientific meeting of the American Society for Reconstructive Microsurgery, Las Vegas, NV, 2012). This may be related to surgical technique as well as potential biological differences in bone healing after induction therapy for immunosuppression. Although these issues present theoretical risks, large enough numbers of transplantations and their complications
J Hand Surg Am.
REFERENCES 1. Hartzell TL, Benhaim P, Imbriglia JE, et al. Surgical and technical aspects of hand transplantation: is it just another replant? Hand Clin. 2011;27(4):521e530. 2. Azari KK, Imbriglia JE, Goitz RJ, et al. Technical aspects of the recipient operation in hand transplantation. J Reconstr Microsurg. 2012;28(1):27e34. 3. Delmas PD. Osteoporosis in patients with organ transplants: a neglected problem. Lancet. 2001;357(9253):325e326. 4. Maalouf NM, Shane E. Osteoporosis after solid organ transplantation. J Clin Endocrinol Metab. 2005;90(4):2456e2465. 5. Matsunaga T, Shigetomi M, Hashimoto T, et al. Effects of bisphosphonate treatment on bone repair under immunosuppression using cyclosporine A in adult rats. Osteoporos Int. 2007;18(11): 1531e1540. 6. Luria S, Lauder AJ, Trumble TE. Comparison of ulnar-shortening osteotomy with a new Trimed dynamic compression system versus the Synthes dynamic compression system: clinical study. J Hand Surg Am. 2008;33(9):1493e1497. 7. Rayhack JM. Technique of ulnar shortening. Tech Hand Up Extrem Surg. 2007;11(1):57e65. 8. Sunil TM, Wolff TW, Scheker LR, McCabe SJ, Gupta A. A comparative study of ulnar-shortening osteotomy by the freehand technique versus the Rayhack technique. J Hand Surg Am. 2006;31(2): 252e257.
r
Vol. 39, January 2014
Forearm Transplantation Osteosynthesis Using Modified Ulnar Shortening Osteotomy Technique James P. Higgins, MD, Jaimie T. Shores, MD, Ryan D. Katz, MD, W. P. Andrew Lee, MD, Bruce S. Wolock, MD
Surgical Technique
One of the challenges of forearm-level hand transplantation surgery is the achievement of osseous union of the ulna given the substantial soft tissue dissection, the use of immune modulating medications, and the diaphyseal level of osseous coaptation. Modification of the conventional surgical technique for an elective ulnar shortening osteotomy provides the advantages of precise osteotomy alignment, a large contact surface oblique osteotomy, and lag screw and compression plating technique. A step-by-step description of the developed modification is provided with a case example. (J Hand Surg Am. 2014;39(1):134e142. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Key words Hand transplantation, ulnar shortening osteotomy, ulnar nonunion, compression plating.
O
of upper extremity allotransplantation is the application of conventional hand surgical techniques to the unique requirements of coapting tissue from donor to recipient. Upon first glance, forearm-level transplantation may seem to pose the same challenges of the more familiar craft of replantation. However, muscle, nerve, and bone coaptation need not occur at the level of the amputation stump because more tissue is available than is needed. Muscle coaptation, for example, may be purposefully performed at the muscles’ origins to preserve entire musculotendinous units, whereas nerve coaptation may be planned as distally as possible to minimize the period of reinnervation. Coaptation of the osseous elements is likewise different from replantation.1,2 NE OF THE MANY CHALLENGES
From the Curtis National Hand Center, MedStar Union Memorial Hospital; and the Department of Plastic and Reconstructive Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Received for publication June 12, 2013; accepted in revised form October 16, 2013. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: James P. Higgins, MD, care of Anne Mattson, the Curtis National Hand Center, MedStar Union Memorial Hospital, 3333 North Calvert Street, Mezzanine, Baltimore, MD 21218; e-mail: [email protected]. 0363-5023/14/3901-0026$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2013.10.005
134
r
Ó 2014 ASSH
r
Published by Elsevier, Inc. All rights reserved.
Osseous coaptation may be planned as distally as possible while permitting resection of poor-quality bone from the amputation stump. Additional resection is avoided to preserve length of the stump in the unfortunate setting of loss of the transplanted part.1,2 In addition, a hybrid osteosynthesis is created by similarly, but not identically, sized skeletal structures. This may permit the alignment of only 1 cortical surface during plating and yield a marked difference in the respective interosseous intervals proximal and distal to the site of osteosynthesis. Whether the osteosynthesis is diaphyseal, metadiaphyseal, or metaphyseal, concern for osseous nonunion (particularly ulnar) after transplantation exists because of the required concomitant use of immune modulating medications3e5 and the relatively large area of surgical exposure or dissection. (Shores JT. ASRT Update: complications to date— the bad and the ugly [hand transplantation]. Presented at the annual scientific meeting of the American Society for Reconstructive Microsurgery, Las Vegas, NV, 2012.) Conventional transverse osteotomy compression plating technique presents technical challenges. The transverse osteotomy provides minimal surface area for coaptation. The creation of exacting transverse, oblique, or step-cut osteotomies with freehand use of bone saws may be imprecise, particularly with the potentially diverse morphology of the donor and
MODIFIED USO PLATING IN HAND TRANSPLANTATION
135
3 bicortical screws on both sides of the osteotomy with an additional precise 3.2-mm oblique lag screw. Other commercial USO systems we evaluated did not offer all of these attributes.
recipient ulnar components. Our team sought to minimize the potential for imprecision, maximize the area of contact, and achieve maximal compression. This goal was sought with great value placed on speed and reproducibility because this would be performed before reperfusion of the transplanted part. Elective ulnar shortening osteotomy (USO) has evolved in the use of commercially available implants that enable the surgeon to rapidly and reproducibly create precise oblique osteotomies to maximize the contact area for osteosynthesis and achieve both dynamic and lag screw compression. The limited studies available on these devices demonstrate outstanding success.6,7 Only 1 retrospective study favorably compared nonunion rates using 1 such device (0 of 52 cases) with freehand osteotomy and compression plating (3 of 45 cases), but failed to demonstrate statistical significance.8 To ensure greatest precision, USO implants are designed to achieve fixation on both sides of the proposed shortening site before osteotomy. Modification of this technique is required to enable its application to the separate and often dissimilar donor and recipient ulnae. A stepwise description of this modification is provided.
Forearm transplant USO technique The TriMed USO system provides 1 universal plate that is used for both right and left arms. The direction of the lag screw is determined by whether it is a right or left arm and whether the plate is positioned volarly or dorsally. The plate is put on volarly on the left arm (and dorsally on the right) at the proximal forearm stump. This enables the drill guide to be attached over the subcutaneous surface of the ulna. This orientation also ensures that the sliding hole is on the distal (donor) part, and the lag screw trajectory is from proximal to distal (Fig. 1). The plate is attached to the proximal (recipient) ulna, first taking care to make sure that it is aligned with the long axis of the ulna. All 3 proximal screws should be placed, leaving the lag screw hole open (and anticipating the lag screw being directed from proximal to distal). This can be performed by the recipient limb preparation team before receiving the prepared donor arm.
TECHNIQUE Implant selection Forearm-level osteosynthesis normally mandates the use of conventional 3.5-mm compression plating. We selected the TriMed USO system (TriMed, Inc., Santa Clarita, CA) because it closely approximates the strength and caliber of conventional forearm plating. Favorable characteristics included its stout stainless-steel design and composition, its use of 3.2-mm screws throughout, and its ability to obtain
Step 1: The plate is placed volarly on the left recipient ulna (dorsally on a right forearm transplant) with 3 screws in the proximal end of the plate, leaving the obliquely oriented lag screw hole proximal (directed distally). The “B” angled saw guide is then used to cut the ulna with an oblique osteotomy. This is performed as distally as possible so that only the minimal amount of bone will be lost in an effort to obtain an oblique osteotomy. The plate is left in place on the proximal stump (Fig. 2).
J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
FIGURE 1: Representation of prepared left forearm-level recipient amputation stump with volar positioned plate directing lag screw hole in a distal trajectory. Ulna is shown with unprepared transverse bone amputation.
136
MODIFIED USO PLATING IN HAND TRANSPLANTATION
Surgical Technique FIGURE 2: Representation of “B” saw guide affixed to side of plate to enable creation of precise oblique osteotomy. Inset demonstrates the position of the saw guide to require minimal bone resection while achieving desired angled osteotomy.
Step 2: The donor arm is brought into the field after preparation by the donor forearm team (described subsequently). The donor arm has previously been prepared with a transverse osteotomy. The donor ulna is placed against the plate, clamping it distally so that it is aligned with the proximal ulna (Fig. 3). The osteotomy is then freehand-revised to be oblique and parallel to the proximal stump osteotomy. The intervening triangular bone segment is removed (Fig. 4). After releasing the clamp on the distal part, the 2 segments are brought into close opposition and the clamps are replaced securing the distal part to the plate. The slotted-hole screw is inserted as far away from the osteotomy as possible to hold the approximation of the distal plate. This slotted screw and a bone clamp (around the plate and the distal ulna) are used to hold longitudinal alignment (Fig. 5). Step 3: A 5-mm resection “A” saw guide is attached to the plate. A sagittal saw is used through the guide to resect 5 mm on the distal piece. This 5-mm resection J Hand Surg Am.
should ensure complete correction of any lack of parallel alignment of the previous freehanded osteotomy (Fig. 6). The TriMed compression clamp is then applied. There is only 1 way that the clamp can be applied, so inappropriate application is not possible. One talon of this device inserts into the only hole in the edge of the plate that will accommodate it. The other talon of the clamp is cannulated. A K-wire should be driven through the cannulated clamp sleeve into the subcutaneous surface of the ulna, dorsal to the midaxis of the bone (volar to the midaxis of the ulna if the plate is applied dorsally on a right arm transplant). This position enables the clamp to prevent the distal ulna from migrating off the plate when compression is applied to the osteotomy (Fig. 7). The sliding screw should then be loosened a quarter turn. Compression is applied with the clamp. The oblique lag screw guide is then mounted onto the plate. The authors have found it helpful to secure the lag screw drill guide and the compressed r
Vol. 39, January 2014
137
FIGURE 3: A Cadaver model demonstrating placement of the donor arm abutting the prepared recipient angled osteotomy. The clamp is applied for longitudinal alignment and stability. B Magnified view of placement.
FIGURE 4: Cadaver model demonstrating the freehand performed roughly parallel osteotomy made in the donor ulna. The clamp maintains longitudinal alignment and stability.
in the standard fashion. The K-wire and compression clamp may then be removed (Fig. 9). Step 5: Attention is then directed to the radius. Ideally, there should be approximately 2 cm overlap between the 2 radii at this point (Fig. 10A). The donor arm has had 2 transverse Kwires placed across the interosseous membrane (IOM) just proximal to the distal radioulnar joint to maintain neutral rotation and native ulnar variance (described subsequently). With the 2 radii overlapping, a freehand transverse sagittal
osteotomy site with a bone clamp applied, as shown in Fig. 8. Step 4: The lag screw hole is drilled using the mounted drill guide. All screws are 3.2 and all use the same size drill (including the lag screw, which is partially threaded and thus does not need a larger proximal drill hole). The lag screw is measured and firmly applied. The plate now has all 4 proximal screws in place. The distal sliding-hole screw is tightened and then the remaining 2 bicortical screws in the distal segment are applied J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
138
MODIFIED USO PLATING IN HAND TRANSPLANTATION
FIGURE 5: Cadaver model demonstrating approximations of the roughly parallel osteotomies. A screw is placed in the distal-most position in the slotted screw hole, providing longitudinal alignment and stability of the distal segment with the clamp.
Surgical Technique FIGURE 6: Representation of 5-mm “A” saw guide affixed to side of plate to enable creation of precise oblique osteotomy in the distal bone segment to mimic the proximal osteotomy. Inset demonstrates the position of the saw guide and the correction of the less precise previous freehand osteotomy.
With the parallel alignment of the osteotomies perfected, attention is turned to rotational alignment. The IOM emanates from the medial aspect of the radius at the acute interosseous ridge that provides a landmark for rotational alignment. At this point in the procedure, the ulna has been fixed securely and the
saw osteotomy is performed. The initial cut can be made purposefully, resulting in 1 to 2 mm of overlap. This enables the surgeon to assess the quality and parallel alignment of the initial osteotomy. If it is inaccurate, it may then be improved with a more parallel subsequent cut. J Hand Surg Am.
r
Vol. 39, January 2014
139
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
FIGURE 7: Representation of the compression clamp affixed to side of the plate to enable closure of the 5-mm gap after slight loosening of the slotted-hole screw and distal clamp.
could be measured preoperatively on the patient’s native contralateral forearm x-ray from olecranon to ulnar styloid. In cases of bilateral transplantation where the contralateral transplantation is also at forearm level, the desired length can be estimated preoperatively based on both the donor and recipient skeletal dimensions, considering the advantages of shorter total forearm length on nerve and tendon coaptation. Finally, in a case of bilateral transplantation in which the contralateral side is performed above-elbow; the ideal total length of the operative ulna will be determined by x-ray measurements of the donor ulna. This desired ulnar length should be communicated to the teams working on both the donor and recipient operative tables. The donor team should affix the forearm in neutral rotation with provisional intraoperative K-wires driven across the IOM proximal to the distal radioulnar joint. This will ensure neutral forearm rotation, preservation of the donor’s native
distal portion of the radius is held in neutral rotation to the distal ulna by the provisional K-wires. It is still possible, however, to neglect proper rotation because the proximal radius is free to rotate. Taking care to align pronosupination, the radius may be plated volarly in compression with a stainless-steel, 3.5-mm dynamic compression plate. It is logical to affix the plate on the radius proximally first, then drill a distal hole in compression mode (Fig. 10B). Next the K-wires holding rotation and variance are removed to permit dynamic compression. Finally, dynamic screw compression is obtained in the drilled hole. The remaining distal holes can be used for bicortical screw fixation in the standard fashion (Fig. 10C). Achieving appropriate forearm length The desired total length of the operative ulna is dictated by a measured length of the patient’s opposite ulna. In the setting of unilateral transplantation, this J Hand Surg Am.
r
Vol. 39, January 2014
140
MODIFIED USO PLATING IN HAND TRANSPLANTATION
Surgical Technique FIGURE 8: Representation of the instrumentation configuration after compression of the osteosynthesis site and lag screw guide application for precise drilling across the osteotomy.
FIGURE 9: Cadaver model demonstrating precise alignment and compression of the oblique osteotomy. Note the different size and morphology of the donor and recipient ulnae.
ulnar variance, and appropriate native tension of the donor’s IOM/distal radioulnar joint alignment before destabilizing the forearm axis. The donor team should await length calculations from the recipient team before performing osteotomies. J Hand Surg Am.
After the recipient team resects the forearm stump back to good-quality bone, the recipient team should perform the oblique plate and guidee directed osteotomy (described in step 1 above). The recipient team should the measure the distance from r
Vol. 39, January 2014
141
FIGURE 10: Cadaver model demonstrating A overlap of the 2 radii after completion of ulnar fixation. B After careful transverse osteotomy of the radii, the 3.5-mm compression plate is affixed volarly on the proximal radius first. Note that the distal radioulnar joint (DRUJ) is held at native length and in neutral rotation by 2 transverse provisional K-wires across the DRUJ of the donor part. C After drilling the first distal hole in compression mode, the DRUJ K-wires are removed and conventional compression plating technique is used to complete fixation in neutral rotation.
FIGURE 11: A Preoperative lateral and B anteroposterior radiographs of a forearm-level transplant recipient’s left arm. C Postoperative radiographs of same patient 4 months after transplantation, demonstrating osteosynthesis of both radius and ulna. The ulna progressed faster and demonstrates greater callus formation.
J Hand Surg Am.
r
Vol. 39, January 2014
Surgical Technique
MODIFIED USO PLATING IN HAND TRANSPLANTATION
142
MODIFIED USO PLATING IN HAND TRANSPLANTATION
have not been reported to determine the prevalence or associated factors influencing ulnar healing. The procedure described here was developed to improve on the surgical technique to minimize risk of ulnar nonunion. Although the precision and compression achievable with USO plating technique for the ulna are desirable, consideration must be given to the complexity of the technique and its potential to lengthen operative time. We have found that meticulous rehearsal and team coordination have limited the osteosynthesis time to approximately 30 minutes. This accounts for osteotomy, fixation, and compression of the ulna. Operative times of 60 minutes for elective ulna shortening osteotomies are reported in the literature using this system and measuring time from skin incision to suture closure.6 Our osteosynthesis time excludes soft tissue exposure and closure because these are performed extensively during other portions of the larger transplant operation.
the recipient olecranon to the tip of remaining stump. The following calculation should be made: Desired total ulnar length Prepared recipient stump length þ 2 cm ¼ Length of donor ulna from styloid to transverse osteotomy
Surgical Technique
This measurement will be communicated back to the donor team so they can plan their ulnar osteotomy. The bone loss of length from the oblique osteotomy should be equal to the thickness of the ulna (because the resection is a triangle with 2 equal sides at 90 ). Ulnar thickness, and thus resection length, can be estimated at 16 mm. This is then added to the additional bone loss from the 5-mm precise resection made with the 5-mm “A” saw guide (see above). This should result in a final length of the operative ulna within a few millimeters of the desired length (as determined above). The donor forearm team should perform the radius osteotomy approximately 2 cm proximal to the precisely measured ulnar osteotomy. The recipient team will plan on having the radius stump equal to or longer than the precisely measured ulnar osteotomy. This will leave the overlap of the radii in the 2- to 4-cm range for correction after the completion of ulnar fixation.
DISCUSSION After significant planning and rehearsal, the use of a USO plating technique described above can maximize the osteosynthesis contact area with a precise oblique osteotomy and achieve reliable, rapid, and reproducible lag and dynamic screw compression to minimize the risk of ulnar nonunion (Fig. 11). The technique also provides a method for achieving the calculated ulnar length desired after transplantation.
COMPLICATIONS Forearm-level transplantation osteosynthesis technique poses challenges unlike those routinely encountered with forearm fractures or forearm replantation. These challenges result from the availability of excess bone, dissimilar morphology of donor and recipient bones and interosseous intervals, lack of landmarks for length determination, and use of postoperative immune-modulating medications. We have experienced a higher than anticipated rate of nonunion of the ulna in cases of forearm-level allotransplantation (3 ulnar nonunions in 2 patients who required surgical intervention; 2 progressed to union and the other required a Darrach resection) (Shores JT. ASRT Update: Complications to date—the bad and the ugly [hand transplantation]. Presented at the annual scientific meeting of the American Society for Reconstructive Microsurgery, Las Vegas, NV, 2012). This may be related to surgical technique as well as potential biological differences in bone healing after induction therapy for immunosuppression. Although these issues present theoretical risks, large enough numbers of transplantations and their complications
J Hand Surg Am.
REFERENCES 1. Hartzell TL, Benhaim P, Imbriglia JE, et al. Surgical and technical aspects of hand transplantation: is it just another replant? Hand Clin. 2011;27(4):521e530. 2. Azari KK, Imbriglia JE, Goitz RJ, et al. Technical aspects of the recipient operation in hand transplantation. J Reconstr Microsurg. 2012;28(1):27e34. 3. Delmas PD. Osteoporosis in patients with organ transplants: a neglected problem. Lancet. 2001;357(9253):325e326. 4. Maalouf NM, Shane E. Osteoporosis after solid organ transplantation. J Clin Endocrinol Metab. 2005;90(4):2456e2465. 5. Matsunaga T, Shigetomi M, Hashimoto T, et al. Effects of bisphosphonate treatment on bone repair under immunosuppression using cyclosporine A in adult rats. Osteoporos Int. 2007;18(11): 1531e1540. 6. Luria S, Lauder AJ, Trumble TE. Comparison of ulnar-shortening osteotomy with a new Trimed dynamic compression system versus the Synthes dynamic compression system: clinical study. J Hand Surg Am. 2008;33(9):1493e1497. 7. Rayhack JM. Technique of ulnar shortening. Tech Hand Up Extrem Surg. 2007;11(1):57e65. 8. Sunil TM, Wolff TW, Scheker LR, McCabe SJ, Gupta A. A comparative study of ulnar-shortening osteotomy by the freehand technique versus the Rayhack technique. J Hand Surg Am. 2006;31(2): 252e257.
r
Vol. 39, January 2014
