40-year-old woman with an open comminuted humeral shaft fracture
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A 40-year-old woman who was obese with osteogenesis imperfecta was involved in a high-speed motor vehicle collision and was brought to the ED after being intubated on the scene for Glasgow Coma Scale of 3.
On presentation, she was found to have polytraumatic injuries, including liver lacerations, mesenteric lacerations, right rib fractures and hemothorax, with orthopedic injuries, including a right, open comminuted diaphyseal humerus fracture (Figure 1), right, vertical shear pelvic ring injury and a right, closed calcaneus fracture. The wound over the right upper extremity was a 1-cm laceration over the mid-posterior brachium. Neurologic exam was unable to be obtained given that she was intubated and sedated.
She had a 2+ right radial pulse. She was taken emergently for exploratory laparotomy by the general surgery team, during which time, her right humerus fracture underwent irrigation and debridement by the orthopedic trauma team through a limited but appropriate posterior approach. She underwent definitive surgical management of her humerus fracture several days later when stable for a prolonged operation.
Source: Michael Githens, MD
What are the best next steps in management of this patient?
See answer below.
Modified posterior Gerwin approach
Given her truncal and peripheral obesity, nonoperative treatment in a Sarmiento brace would likely result in persistent varus angulation, provide inadequate stability for union and potentially result in skin problems. In addition, debridement of an open fracture results in evacuation of fracture hematoma, thus decreasing her probability of union via the endochondral ossification pathway. Our goal was to treat her multifragmentary fracture with absolute stability given the large size of the fragments, compressible surfaces, and previous hematoma evacuation. A secondary goal specific to the patient’s history of osteogenesis imperfecta, was to maximize implant length to protect against future peri-implant fracture.
Surgical procedure
Following the induction of general anesthesia, the patient was positioned lateral decubitus on the operating table (a radiolucent cantilever-type bed in the reverse position). The right upper extremity was placed on a radiolucent arm board, with the down arm positioned on a well-padded plexiglass board, out of the way of imaging the operative arm.
The posterior incision that had been previously created for debridement was extended proximally and distally for an extensile posterior exposure. Skin, subcutaneous tissue and triceps fascia were divided sharply. A careful extra-periosteal lateral paratricipital exposure to the humerus distal to the fracture was performed. The radial nerve and its sensory branches were then identified, mobilized and protected throughout the case. The nerve was contused, not unexpectedly given the fracture location and pattern. Proximally, a modification of the approach described by Gerwin was utilized to access the proximal segment and maximize implant length given the patient’s history of osteogenesis imperfecta. Extra-periosteal exposure of the lateral and posterior humerus above the fracture was carried up to the origin of the lateral head of the triceps. Rather than taking the lateral head down as described by Gerwin, the lateral head origin is preserved, and a window between the lateral and long heads of the triceps and the inferior border of the posterior deltoid is developed. The posterior humerus is accessed through this window allowing tunneling of the plate under the lateral head of the triceps (Figure 2). Proximally, the posterior deltoid along with the axillary nerve and posterior humeral circumflex vessels are elevated off the posterior cortex in a sub-periosteal fashion and retracted to allow more proximal implant placement. Lastly, the fracture fragments were exposed and carefully cleaned, maintaining as much muscular attachment, periosteum and hematoma as possible.
A direct reduction strategy was then deployed, working from proximal to distal, sequentially clamping fracture fragments with a combination of small Weber and modified straight-straight Weber clamps. A series of 2.4-mm interfragmentary screws were then placed across compressible fracture lines to function as permanent clamp replacements (Figure 3).
Next, a posterior plate was contoured with a bit of over-contour to compress the anterior cortical fracture lines during plate application. The plate was passed underneath the radial nerve, tunneled underneath the proximal triceps and carefully placed underneath the posterior border of the patient’s deltoid, teres minor and axillary neurovascular bundle. Plate position was confirmed fluoroscopically, with the last screw bisecting the capitellum. The plate was then fixed with four screws proximal to the fracture and four screws distal to the fracture, functioning as a neutralization plate. Final fluoroscopic views were obtained and reviewed, confirming high-quality reduction, stable fixation and safe implant position (Figure 4). The wounds were irrigated and closed in a layered fashion. Sterile dressings were applied. Final flat plate radiographs were obtained and reviewed at the termination of the case. She was made coffee cup weight-bearing in the operative extremity for 6 weeks.
Follow-up
During the patient’s inpatient postoperative stay, after she was extubated, she was noted to have motor and sensory radial nerve palsy during the first 2 weeks postoperatively. At 3 weeks postoperatively, her radial nerve palsy was noted to be completely resolved. At 6 weeks following surgery at her outpatient visit, the patient reported no numbness or weakness, and no pain in her arm.
On exam, she had a completely resolved radial nerve palsy with full sensation and motor nerve function. Radiographs at this visit demonstrated evidence of interval healing, no change in alignment of the fracture and no change in implant positioning (Figure 5). She was satisfied with her function and released for weight-bearing as tolerated, with no heavy lifting for 6 more weeks.
Discussion
Several approaches to the humeral shaft have been described: percutaneous, anterior, anterolateral, posterior transtricipital and modified posterior approach as described by Gerwin. The latter is mostly muscle sparing and provides greater exposure to the humerus than the posterior transtricipital approach, while also allowing exploration of the radial nerve. The modified Gerwin approach involves retracting the medial and lateral heads of the triceps medially, while identifying the radial nerve sensory branches including the lower lateral brachial cutaneous nerve which crosses into the posterior aspect of the lateral intermuscular septum. This approach allows the radial nerve to be retracted medially, which allows further exposure of the humeral shaft, a mean of 26 cm of exposure proximally from the lateral epicondyle.
In this case, the authors describe the use of a modification of the approach described by Gerwin, which is entirely muscle sparing and allows access to nearly the entire posterior humerus. While, to our knowledge, this modified approach is not described in the literature, it has proven to be safe and useful for certain fracture patterns in the senior author’s experience. Several key elements of the exposure should be highlighted to ensure safe dissection proximally. When developing the interval between the lateral and long heads of the triceps, the surgeon must be acutely aware of the quadrangular space and its contents, directly medial to the humerus at this level. Errant pass of retractors or other instrumentation into this space risk injury to the posterior circumflex vessels or axillary nerve. When dissecting along the posterior cortex proximally underneath the deltoid, a sub-periosteal exposure with a periosteal elevator allows safe retraction of the axillary nerve along with the posterior deltoid. In some patients, the teres minor may prevent plate application as proximally as demonstrated in this case.
In this case, an absolute stability strategy was selected given the size of cortical fragments and their compressibility. The success of this tactic hinges upon limited soft tissue dissection on the individual fragments, maintaining as much periosteum and muscle as possible to preserve their vascularity. In patients with osteogenesis imperfecta, an implant spanning the entire bone is desirable to mitigate the risk of future fracture, which is common in this patient population. The modification of the Gerwin approach described here provides excellent exposure for extensile posterior plating, as well as safe exposure of the radial nerve and its branches.
Key points:
- When using an absolute stability strategy for multifragmentary fracture patterns, the surgeon must take great care to preserve the vascularity of fragments to avoid generating a nonunion.
- The modified Gerwin approach allows greater exposure of the posterior humerus than the transtricipital posterior approach, and further proximal exposure can be obtained by developing the interval between the heads of the triceps and carefully retracting the posterior deltoid and axillary nerve.
- References:
- Gerwin M, et al. J Bone Joint Surg Am. 1996;doi:10.2106/00004623-199611000-00008.
- Orapiriyakul W, et al. J Clin Orthop Trauma. 2023;doi:10.1016/j.jcot.2023.102230.
- For more information:
- Michael Githens, MD, can be reached at the department of orthopedic surgery at Harborview Medical Center at the University of Washington. Pooja Prabhakar, MD, can be reached at the department of orthopaedics and sports medicine at the University of Washington Medical Center. Prabhakar’s email: prabhaka@uw.edu.
- Edited by Andrew Bi, MD, and Pooja Prabhakar, MD. Bi is a chief resident in the department of orthopedic surgery at NYU Langone. He will pursue a fellowship in sports medicine at Rush University Medical center following residency completion. Prabhakar is a chief resident in the department of orthopaedic surgery at the University of Washington. She will pursue a fellowship in foot and ankle surgery at Baylor University Medical Center following residency completion. For more information on submitting Orthopedics Today Grand Rounds cases, please email orthopedics@healio.com.
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