A vertical skin incision was then made around the wire, and the 4.5-mm cannulated drill was placed over the wire. A soft-tissue protective drill sleeve and oscillating technique were used to protect the soft-tissue anatomy. The trajectory of the drill was again confirmed on pelvic OOOCI and advanced into the bone. The intended path of the drill was from the cranial-medial symphyseal cortex of the contralateral superior ramus, through the symphysis pubis obliquely, and then into the medullary canal of the affected inferior ramus. Frequent biplanar fluoroscopic imaging followed this progression of the drill to the nonunion site. The cannulated drill was then removed and exchanged for a calibrated extra-long 2.5-mm drill bit, placed through the soft-tissue drill sleeve and into the glide hole created by the 4.5-mm cannulated drill. The C-arm unit ensured accurate positioning of the 2.5-mm drill on both pelvic OOOCI and “excessive” inlet view before advancement (Figures 3A, 3B). The 2.5-mm drill was advanced caudally, laterally, and anteriorly in the ramus, past the nonunion site, and then was stopped before it exited the cortex of the ischial tuberosity (Figures 4A, 4B).
The depth of the drill bit was assessed with a known-length protective drill sleeve and calibrated drill. Alternatively, depth can be assessed with another same-length calibrated drill bit positioned adjacent to the inserted drill bit. A fully threaded, blunt-tipped 4.5-mm cortical screw was then placed through the glide hole. Both fluoroscopic views were used to confirm that the screw followed the same trajectory as the drill. Finally, the screw was again checked on biplanar fluoroscopy to confirm it had remained in the OFP of the inferior ramus (Figures 5A, 5B).
Postoperative pelvic CT confirmed position and length of the screws. The patient was allowed weight-of-limb weight-bearing on her affected side after surgery. She was discharged the first day after surgery and allowed use of oral analgesics. Six weeks after surgery, pelvic radiographs showed partial healing, and she reported symptom relief. Resistive strengthening exercises were instituted, and progressive weight-bearing proceeded to full weight-bearing over the next 6 weeks. The patient reported almost complete relief of pain by 3 months, and she was able to return to work and daily activities without medication. Radiographs showed consolidation of the fractures. She was essentially symptom-free 17 months after surgery (Figure 6).
Case 2
An obese 51-year-old woman presented to the orthopedic clinic with a 6-month history of left groin pain that worsened with ambulation. She did not recall a specific injury but acknowledged a history of previous falls. Past medical history was significant for ulcerative colitis/irritable bowel syndrome and degenerative disease in the lumbar spine and right ankle. Previous pelvic radiographs showed no evidence of fracture or abnormality, but radiographs obtained before evaluation in the clinic showed hypertrophic nonunion of the left superior and inferior pubic ramus.
The patient had pain deep in the left groin with weight-bearing. On physical examination, she denied pain with log roll of the left hip or resisted straight leg raise. The pelvis was stable to manual compression. There was no sign of hernia or lymphadenopathy in the region of the left groin.
The patient had obtained a technetium-99 nuclear medicine scan of the pelvis in addition to standard preoperative CT of the nonunion area. The nuclear medicine scan showed uptake in the area of the superior and inferior ramus, and CT confirmed presence of a superior and inferior ramus that would accommodate a medullary screw.
The patient was taken to the operating room, where percutaneous fixation of the left superior and inferior ramus was performed (as described above). The patient was discharged on postoperative day 2 and followed the same weight-bearing protocol that the first patient used.
At 6 weeks, the patient returned to clinic with improved comfort. At 3 months, she denied left groin pain and was limited in activity only by preexisting arthrosis in the left ankle and lumbar spine. She was using a walker only for long distances and was symptom-free 13 months after surgery.
Discussion
Acute surgical fixation of the inferior ramus is seldom performed. The anatomical location of the inferior ramus and the lack of defined criteria for fixation often leave the inferior ramus ignored, unreduced, and without stabilization. In the setting of symptomatic nonunion, open stabilization has been used.11,12 Plate fixation after open débridement of an inferior ramus nonunion requires more extensive dissection and may increase the risk for perioperative infection and hardware prominence compared with an intramedullary implant.14 If plate prominence becomes symptomatic, the plate must be removed in a second surgical procedure. Percutaneous medullary screw fixation avoids the risks of surgical soft-tissue dissection and placement of a surface implant on the bone and reduces the need for a second surgical procedure to remove bothersome hardware. Percutaneous pelvic fixation has been well described and shown to provide stability to the pelvis. It can also be used to treat hypertrophic nonunions of the pelvis when mechanical stability is required for healing.13