Intraoperative somatosensory evoked potential monitoring during acute pelvic fracture surgery

Is intraoperative neuromonitoring effective in hip and pelvis orthopedic and trauma surgery? A systematic review

INTRODUCTION

Sciatic nerve injury is an uncommon but potentially devastating complication in hip and pelvis surgery. Intraoperative nerve monitoring (IONM) was applied since the seventies in neurosurgery and spine surgery. Nowadays, IONM has gained popularity in other surgical specialities including orthopaedic and trauma surgery. Aim of this systematic review is to resume the literature evidences about the effectiveness of intraoperative monitoring of sciatic nerve during pelvic and hip surgery.

METHODS

Two reviewers (GC and MD) independently identified studies by a systematic search of PubMed and Google Scholar from inception of database to 10 January 2021. Inclusion criteria were: (a) English written papers, (b) use of any type of intraoperative nerve monitoring during traumatic or elective pelvic and hip surgery, (c) comparison of the outcomes between patients who underwent nerve monitoring and patient who underwent standard procedures, (d) all study types including case reports. The present review was conducted in accordance with the 2009 PRISMA statement.

RESULTS

The literature search produced 224 papers from PubMed and 594 from Google Scholar, with a total amount of 818 papers. The two reviewer excluded 683 papers by title or duplicates. Of the 135 remaining, 72 were excluded after reading the abstract, and 31 by reading the full text. Thus, 32 papers were finally included in the review.

CONCLUSIONS

The use of IONM during hip and pelvis surgery is debated. The review results are insufficient to support the routine use of IONM in hip and pelvis surgery. The different IONM techniques have peculiar advantages and disadvantages and differences in sensitivity and specificity without clear evidence of superiority for any. Results from different studies and different interventions are often in contrast. However, there is general agreement in recognizing a role for IONM to define the critical maneuvers, positions or pathologies that could lead to sciatic nerve intraoperative damage.

LEVEL OF EVIDENCE

Level 2.

Management of Pelvic Ring Injury Patients With Hemodynamic Instability

Pelvic ring injuries (PRI) are among the most difficult injuries to deal with in orthopedic trauma. When these injuries are accompanied by hemodynamic instability their management becomes significantly more complex. A methodical assessment and expeditious triage are required for these patients followed by adequate resuscitation. A major triage decision is whether these patients should undergo arterial embolization in the angiography suit or prompt packing and pelvic stabilization in the operating room. Patient characteristics, fracture type and injury characteristics are taken into consideration in the decision-making process. In this review we discuss the acute evaluation, triage and management of PRIs associated with hemodynamic instability. An evidence based and protocol driven approach is necessary in order to achieve optimal outcomes in these patients.

Neurophysiologic monitoring can predict iatrogenic injury during acetabular and pelvic fracture fixation

BACKGROUND

Nerve injury during acetabular and pelvic fracture fixation can have devastating consequences for trauma patients already in a compromised situation.

QUESTIONS/PURPOSES

This study aims to evaluate the efficacy of multimodality intraoperative neurophysiologic monitoring during acetabular and pelvic fracture fixation in identifying emerging iatrogenic nerve injury.

METHODS

Sixty patients were retrospectively identified after surgical fixation following acetabular or pelvic fracture. Neuromonitoring during surgery was performed using three different modalities, transcranial electric motor evoked potential (tceMEP), somatosensory evoked potential (SSEP), and electromyographic (EMG) monitoring. Each modality was evaluated for sensitivity and specificity of detecting an intraoperative nerve injury.

RESULTS

tceMEP monitoring was found to be 100% sensitive and 86% specific at detecting an impending nerve injury. The sensitivity and specificity of SSEP were 75% and 94%, while EMG sensitivity was unacceptably low at 20% although specificity was 93%.

CONCLUSIONS

Multimodality neuromonitoring of transcranial electric motor and peroneal nerve somatosensory evoked potentials with or without spontaneous EMG monitoring is a safe and effective method for detecting impending nerve injury during acetabular and pelvic surgery.

Intraosseous correction of misdirected cannulated screws and fracture malalignment using a bent tip 2.0 mm guidewire: technique and indications

Percutaneous pelvic screw placement is a technically demanding procedure. A precise intraosseous pathway must be prepared before screw placement into any osseous fixation pathway of the pelvis. Adjustments to a drill or guidewire become increasingly difficult as the instrument is advanced within the pelvis. We present a reliable and reproducible technique using a 2.0 mm guidewire that allows for correction of an initially misdirected drill within the pelvis. This technique also allows for manipulation and reduction of certain malaligned pelvic fractures prior to percutaneous cannulated screw placement. This technique does not substitute for poor surgical technique but is used to optimize the position of percutaneously placed pelvic screws.

The outcome of surgically treated traumatic unstable pelvic fractures by open reduction and internal fixation

BACKGROUND

This study was performed to evaluate functional and radiological results of pelvic ring fractures treatment by open reduction and internal fixation.

METHODS

Thirty eight patients with unstable pelvic fractures, treated from 2002 to 2008 were retrospectively reviewed. The mean patients' age was 37 years (range 20 to 67). Twenty six patients were men (4 patients with type B and 22 patients with type C fracture) and 12 women (7 patients with type B and 5 patients with type C fracture). The commonest cause was a road traffic accident (N=37, about 97%). Internal fixation was done by plaque with ilioinguinal and Kocher-Langenbeek approaches for anterior, posterior pelvic wall and acetabulum fracture respectively. Quality of reduction was graded according to Majeed score system.

RESULTS

There were 11 type-C and 27 type-B pelvic fractures according to Tile's classification. Thirty six patients sustained additional injuries. The commonest additional injury was lower extremity fracture. The mean follow-up was 45.6 months (range 16 to 84 months).The functional outcome was excellent in 66%, good in 15%, fair in 11% and poor in 7% of the patients with type B pelvic fractures and functional outcome was excellent in 46%, good in 27%, fair in 27% and poor in 0% of the patients with type C pelvic fractures. There were four postoperative infections. No sexual functional problem was reported. Neurologic problem like Lateral cutaneous nerve of thigh injury recovered completely in 2 patients and partially in 2 patients. There was no significant relation between functional outcome and the site of fracture (P greater than 0.005).

CONCLUSIONS

Unstable pelvic ring fracture injuries should be managed surgically by rigid stabilization. It must be carried out as soon as the general condition of the patient permits, and even up to two weeks.

Sciatic nerve injury associated with acetabular fractures

Sciatic nerve injuries associated with acetabular fractures may be a result of the initial trauma or injury at the time of surgical reconstruction. Patients may present with a broad range of symptoms ranging from radiculopathy to foot drop. There are several posttraumatic, perioperative, and postoperative causes for sciatic nerve palsy including fracture-dislocation of the hip joint, excessive tension or inappropriate placement of retractors, instrument- or implant-related complications, heterotopic ossification, hematoma, and scarring. Natural history studies suggest that nerve recovery depends on several factors. Prevention requires attention to intraoperative limb positioning, retractor placement, and instrumentation. Somatosensory evoked potentials and spontaneous electromyography may help minimize iatrogenic nerve injury. Heterotopic ossification prophylaxis can help reduce delayed sciatic nerve entrapment. Reports on sciatic nerve decompression are not uniformly consistent but appear to have better outcomes for sensory than motor neuropathy.

Sciatic nerve release following fracture or reconstructive surgery of the acetabulum. Surgical technique

BACKGROUND

Sciatic neuropathy associated with acetabular fractures can result in disabling long-term symptoms. The purpose of this retrospective study was to evaluate the effect of sciatic nerve release on sciatic neuropathy associated with acetabular fractures and reconstructive acetabular surgery.

METHODS

Between 2000 and 2004, ten patients with sciatic neuropathy associated with an acetabular fracture were treated with release of the sciatic nerve from scar tissue and heterotopic bone. Additional surgical procedures included open reduction and internal fixation of the acetabulum (five patients), removal of hardware and total hip arthroplasty (three patients), and removal of hardware alone (one patient). The average age of the patients was forty-three years. All patients were followed with serial examinations and assessments for a minimum of one year (average, twenty-six months).

RESULTS

All patients had partial to complete relief of radicular pain, of diminished sensation, and of paresthesias after the nerve release. Four of seven patients with motor loss and two of five patients with a footdrop demonstrated improvement in function after the nerve release. No patient had evidence of worsening on neurologic examination after the release.

CONCLUSIONS

Sciatic nerve release during reconstructive acetabular surgery can decrease the sensory symptoms of preoperative sciatic neuropathy associated with a previous acetabular fracture. Motor symptoms, however, are less likely to resolve following nerve release.

Simultaneous anterior and posterior approaches for complex acetabular fractures

Simultaneous Kocher-Langenbeck and iliofemoral exposures of the acetabulum are a safe and useful alternative to other extensile exposures and can be performed with similar morbidity. The advantages of simultaneous anterior and posterior approaches over extensile exposures include the absence of a trochanteric osteotomy. The combined approach is most useful in transverse, transverse posterior wall fractures with wide anterior displacement, T type fractures with significant anterior-inferior displacement, or both column fractures with posterior wall involvement.

Unstable sacral fractures: associated injuries and morbidity at 1 year

STUDY DESIGN

A prospective, longitudinal single-cohort study of 32 patients treated with internal fixation for unstable sacral fractures.

OBJECTIVES

To describe the prevalence of associated injuries in blunt pelvic trauma with unstable sacral fractures, and to characterize late impairments.

SUMMARY OF BACKGROUND DATA

In high-energy pelvic ring injury, the close association of the spine, the intrapelvic organs and the bony pelvic ring result in high risk for additional injuries. These injuries may result in long-term sequels pertaining to mobility, voiding, bowel function, and sexual function. However, little is known about the components of long-term morbidity after unstable sacral fractures.

METHODS

The minimum 1-year follow-up included 32 patients surgically treated for unstable sacral fractures. Patients were analyzed for associated injuries, fracture classification, severity of trauma, and long-term measures of neurologic recovery, mobility, and functions pertaining to voiding, defecation, and sexual function.

RESULTS

Additional injuries occurred in 84%. Injury Severity Score was 27 (range, 9-57). At follow-up, sensory impairments were observed in 91%; impaired gait in 63%, and bladder, bowel, or sexual impairments in 59%. Sacral radiculopathies explained only 60% to 69% of these impairments. The presence of late impairments correlated to the severity of injury and to the presence of associated injuries, but not to fracture characteristics.

CONCLUSIONS

Unstable fractures of the sacrum are frequently associated with additional injuries. These injuries have a significant effect on morbidity still 1 year after injury. The multifactor etiology of impairments after sacral fractures should be acknowledged in the assessment of these patients.

Multisegmental open sacral fracture due to impalement: a case report

We report on an unusual impalement injury to the sacrum in a 15-year-old adolescent patient. This open pelvic fracture resulted in a shattered sacrum with neurologic impairment including clinically absent anal sphincter tone and perineal sensation. Early debridement, wound revision, neural decompression, fracture reduction, and stable fixation using lumbopelvic fixation according to the principles of triangular osteosynthesis resulted in a favorable outcome with primary wound healing, return of bowel and bladder control, as well as immediate patient mobilization.

The significance of anode location for stimulus-evoked electromyography during iliosacral screw placement

OBJECTIVES

To determine the effect of anode location on the current threshold required to provoke an electromyograph response during stimulus-evoked electromyography for iliosacral screw placement.

DESIGN

Prospective cohort.

SETTING

Level I trauma center.

PATIENTS

Nineteen consecutive patients with 23 unstable posterior pelvic ring injuries treated with iliosacral screws.

INTERVENTION

Iliosacral screws were inserted percutaneously over guidewires. Twenty-seven screws were inserted, all into the first sacral vertebrae. The guidewire was used as the cathode for constant-current, stimulus-evoked electromyography for all data collection. Stimulus-evoked electromyographs were obtained with the guidewire at four different stations: at the sacroiliac joint (station I), at the first sacral neuroforamen (station II), in the body of the sacrum (station III), and when the iliosacral screw was in final position over the guidewire (station IV).

MAIN OUTCOME MEASURE

Stimulus-evoked electromyographs were obtained with the anode at four different locations for each of the implant stations. Location A had the anode adjacent to the percutaneous insertion site of the guidewire, location B at the ipsilateral anterior superior iliac spine, location C at the midline, and location D at the contralateral anterior superior iliac spine.

RESULTS

Moving the anode from midline (location C) toward the entry point of the guidewire increased the current threshold required to provoke an EMG response as much as 67.1% (p < 0.05). Moving the anode from midline to the contralateral anterior superior iliac spine decreased thresholds as much as 3.4% (p > 0.05). In one case, anode placement close to the guidewire insertion site (locations A and B) failed to identify a potentially dangerous implant because current thresholds were >8 mA. With the anode at the midline, current thresholds were <8 mA, indicating unsafe guidewire position leading to redirection of the guidewire.

CONCLUSION

The physical location of the anode during stimulus-evoked electromyography monitoring for iliosacral screw placement significantly changes the current thresholds required to provoke an electromyograph response. Current thresholds required to stimulate nerves increase as the anode is moved toward the stimulating electrode. Anode placement ipsilateral to the stimulating electrode may provide a false indication of safe guidewire placement. We recommend anode location at or beyond the midline for stimulus-evoked electromyography monitoring during iliosacral screw placement.

Attitudes of orthopaedic trauma surgeons regarding current controversies in the management of pelvic and acetabular fractures

A closed-ended questionnaire was mailed to all 363 active members of the Orthopaedic Trauma Association. It directed, toward practicing pelvic and acetabular surgeons, questions pertaining to practice demographics and preferred methods for detection and prevention of deep venous thrombosis (DVT), nerve injury, and heterotopic ossification (HO). Questionnaires were received from 226 surgeons (62 percent). Of the surgeons who responded, 181 (80 percent) perform pelvic-fracture and acetabular-fracture surgery; only questionnaires from this group were analyzed. Standard statistical methods were used to perform both univariate and multivariate analyses. Preoperative DVT screening was performed by 48 percent of the surgeons; ultrasound was the most commonly used modality (82 percent). Preoperative DVT prophylaxis was administered by 88 percent of those surveyed; the majority (78 percent) used sequential compression devices. Postoperative prophylaxis was used by 99 percent; the most commonly used modality was sequential compression devices. Analysis suggests that fellowship-trained surgeons and surgeons in practice for fewer than twenty years are more likely to use preoperative DVT prophylaxis. HO prophylaxis was administered by 88 percent; the most commonly used modality was indomethacin. Intraoperative nerve monitoring was performed by only 15 percent of the respondents. Most surgeons employed prophylactic measures to prevent DVT and HO. The wide variation in type of prophylaxis and reasons for use suggests that controversy will continue, and a standard of care for these conditions has yet to be defined. Very few surgeons use intraoperative nerve monitoring routinely.

Unstable pelvic ring disruptions in unstable patients

Management of the patient with a high-energy pelvic fracture requires a multidisciplinary team approach with coordination between the general surgery, orthopaedic surgery, neurosurgery, and urology teams. Resuscitation and initial evaluation efforts are critical in stabilization of the patient. An understanding of the complex nature of the pelvic anatomy and injury patterns, the associated injuries, and various treatment fixation constructs are necessary for a successful outcome. This review outlines the initial stabilization and definitive management for the spectrum of pelvic ring disruptions. Case examples illustrate the discussion.

On the applicability of two different stimulation techniques for intra-operative peroneal nerve conduction testing

Dysfunction of the peroneal nerve is an important complication of knee surgery. We compared two monitoring procedures of peroneal nerve function during a standardized operation, a closing wedge high tibial osteotomy. For two types of stimulation the evoked compound motor unit action potentials (CMAPs) were recorded on the tibialis anterior muscle. We used direct perineural electrical stimulation of the common peroneal nerve distal to the cuff (dCMAPs) after nerve identification in the surgical field. Additionally, magnetic stimulation of the sacral plexus proximal to the cuff (pCMAPs) was performed. It was found that dCMAPs were recorded during almost one hour of tourniquet time whereas the pCMAPs were blocked after 25-30 min in 9 out of 11 cases. On the other hand, the CMAP obtained after proximal stimulation exhibited a latency shift with tourniquet yielding an indicator of ischaemic changes present beneath and distal to the tourniquet cuff. In conclusion, different applicabilities of both stimulation techniques under tourniquet conditions were demonstrated.

Medium- and long-term results of open reduction and internal fixation for unstable pelvic ring fractures

Over a 10-year period, 74 patients with unstable pelvic injuries were treated with open reduction and internal fixation. Radiographic and clinical follow-up averaged 71 months (range: 38-141 months). Satisfactory (ie, good and very good) radiographic results were obtained in 90% of patients. Clinical results were superior in patients without associated injuries (P=.05-.001). Most of the complications in this series were due to associated injuries. Sepsis was mostly due to open pelvic injuries and malunion to either lack of patient cooperation or inadequate open reduction and internal fixation. Careful preoperative analysis of the nature of the pelvic injury and selection of the appropriate operative technique for open reduction and internal fixation result in a satisfactory outcome for the majority of operative patients.

Evaluation of intraoperative nerve-monitoring during insertion of an iliosacral implant in an animal model

BACKGROUND

The use of continuous electromyographic and somatosensory-evoked-potential monitoring systems has been advocated to assist in avoiding nerve-root injury during operations on the pelvic ring. More recently, it was suggested that stimulus-evoked electromyographic monitoring may further decrease the risk of iatrogenic nerve-root injury during posterior pelvic fixation by enabling the surgeon to determine the actual distance of an implant from a nerve root. The purpose of the current study was to evaluate the relative efficacy of these three methods of monitoring for minimizing the risk of neural injury during the placement of iliosacral implants.

METHODS

While the function of the first sacral nerve root was monitored with the use of stimulus-evoked electromyographic, continuous electromyographic, and somatosensory-evoked-potential monitoring techniques, a 2.0-millimeter stainless-steel Kirschner wire was progressively inserted, guided by a high-speed computerized tomographic scanner, into the first sacral body of seventeen hemipelves in nine dogs. The end point was contact with the nerve as demonstrated by the computerized tomographic images. It was expected that this end point would be heralded by a burst of spontaneous electromyographic activity and an abnormal somatosensory-evoked-potential signal. Anatomical dissection at the completion of the study documented the final position of the Kirschner wire.

RESULTS

Anatomical dissection demonstrated compression or penetration of the nerve root in sixteen of the seventeen specimens. A spontaneous burst of electromyographic activity was not recorded for any specimen on continuous electromyographic monitoring; this finding was significantly different from what had been expected (p<0.001). Because of technical problems, somatosensory evoked potentials could be recorded for only twelve hemipelves that had nerve-root compression or penetration, and abnormal somatosensory evoked potentials were recorded for only one of the twelve; this finding was significantly different from what had been expected (p<0.001). A total of 113 stimulus-evoked electromyographic data points were obtained. The correlation coefficient for the relationship between the current threshold recorded with stimulus-evoked electromyographic monitoring and the distance of the wire from the nerve was 0.801 (p<0.001). The actual measured current thresholds were of an observed proportion not different from what had been expected (p = 0.48).

CONCLUSIONS

Continuous electromyographic and somatosensory-evoked-potential monitoring techniques failed to indicate contact with the nerve root reliably in this animal model. However, stimulus-evoked electromyographic monitoring consistently provided reliable information indicating the proximity of the implant to the nerve root.

Intraoperative monitoring with stimulus-evoked electromyography during placement of iliosacral screws. An initial clinical study

A consecutive series of twenty-seven patients who had thirty acute unstable (type-C) fractures of the pelvic ring was studied prospectively to evaluate the use of stimulus-evoked electromyography to decrease the risk of iatrogenic nerve-root injury during the insertion of iliosacral screws. A prerequisite for inclusion in the study was a normal neurological status preoperatively; somatosensory evoked potentials were monitored to further document the neurological status both before and after insertion of the screw or screws. A total of fifty-one iliosacral screws were inserted, and a current threshold of more than eight milliamperes was selected as the level that indicated that the drill-bit was a safe distance from the nerve root. Four of the fifty-one screws were redirected because of information obtained with stimulus-evoked electromyography. Postoperatively, all patients had a normal neurological status. Computerized tomography, although not accurate for detailed measurements, demonstrated that all of the screws were in a safe, intraosseous position. Monitoring with stimulus-evoked electromyography appears to provide reliable data and may decrease the risk of iatrogenic injury to the nerve roots during operations on the pelvic ring.

Intraoperative stimulus-evoked electromyographic monitoring for placement of iliosacral implants: an animal model

OBJECTIVE

A canine model was designed to evaluate the feasibility of stimulus-evoked electromyographic (EMG) monitoring of the lumbosacral nerve roots during the insertion of iliosacral implants.

STUDY DESIGN/METHODS

Four 2.5-millimeter Kirschner wires (K-wires) were percutaneously inserted under general anesthesia into the S1 body of each of five dog hemipelves using C-arm fluoroscopy image-intensifier control in an actual attempt to compromise the S1 canal and the S1 nerve root. A searching current of twenty milliamperes was initially applied to the K-wire with monitoring electrodes placed in the gastrocnemius muscle. Current thresholds required to evoke an EMG response were recorded for each K-wire. Actual K-wire location was determined by anatomical dissection.

RESULTS

Evaluation of these twenty wires revealed that current threshold was directly related to the proximity of the K-wire to the nerve root, with a correlation coefficient of 0.94 (p < 0.001).

CONCLUSIONS

Stimulus-evoked EMG monitoring provided reliable data indicating the proximity of the iliosacral implants to the sacral nerve root. This method of intraoperative nerve monitoring could potentially decrease the risk of iatrogenic nerve root injury during pelvic ring surgery. Further study is warranted.

Neuromonitoring in the operating room: why, when, and how to monitor?

This review considers the main principles and indications of EEG and evoked potential (EP) neuromonitoring in the operating room. Neuromonitoring has a threefold purpose: to warn the surgeon that he has to adjust his strategy, to confirm his decision, and to help him improve subsequent procedures. The pathophysiology of intraoperative events liable to alter the EEG or the EPs is first considered. The usefulness of neuromonitoring in preventing neurological complication relies on its ability to detect neurological dysfunction at a reversible stage. This applies especially to ischemia and compressive damage. The anesthetic influences on EEG and EPs are then considered. Knowledge of them is essential to disentangle these neurophysiological alterations due to intraoperative events from those merely due to anesthesia and to use neurophysiological parameters to evaluate the depth of anesthesia. Third, the main indications and limitations of neuromonitoring are considered: prevention of ischemic brain or spinal cord damage, prevention of mechanical injuries of the brain, spinal cord or peripheral nerve, and localization of the motor cortex in cortical neurosurgery or of cranial nerves in posterior fossa surgery. Finally, the 3 levels of neuromonitoring (neurophysiological feature extraction, neurophysiological pattern recognition, clinical integration of the neurophysiological patterns) are discussed together with the rules that should guide the dialogue between the surgeon, the anesthesiologist, and the neurophysiologist.

Stabilization of pelvic ring disruptions

Pelvic ring disruptions are challenging management problems for the orthopedic surgeon. Early hemorrhage, permanent nerve injury, and late pain caused by residual pelvic deformity are some of the many complicating factors. A variety of treatment alternatives are available to stabilize the disrupted pelvic ring. Each technique has inherent advantages and problems.

Intraoperative monitoring of motor pathways during operative fixation of acute acetabular fractures

OBJECTIVE

To determine whether intra-operative spontaneous electromyography (EMG) was superior to somatosensory evoked potentials (SSEP) in the prevention of iatrogenic sciatic nerve injury.

DESIGN

Prospective, consecutive.

SETTING

Tertiary referral, teaching Hospital in New York City.

PATIENTS

Seventy-four patients with acutely displaced acetabular fractures.

MAIN OUTCOME MEASURE

Group A consisted of 24 patients who underwent intraoperative sciatic nerve monitoring using SSEP only. Group B consisted of 50 patients who underwent monitoring using both SSEP and spontaneous EMG. Motor potentials were recorded from the tibialis anterior, peroneus longus, abductor hallucis, and flexor hallucis longus muscles. All patients had independent preoperative and postoperative evaluations by the same neurologist.

RESULTS

One iatrogenic sciatic nerve injury occurred in group A and none in group B. Prolonged sciatic nerve compromise, demonstrated by significant intraoperative SSEP changes, occurred 2.4 times per case in group A and only 0.8 times per case in group B. In group B, spontaneous EMG noted compromise an average of 3.6 times per case (p < 0.0001).

CONCLUSIONS

The results of this study support spontaneous EMG as feasible and superior to SSEP monitoring in detecting intraoperative sciatic nerve comprise in acute acetabular fracture surgery. Spontaneous EMG permits earlier detection of intraoperative sciatic nerve comprise, allowing a more rapid response of the surgical team to noxious nerve stimuli. This may prevent permanent neurologic sequellae.

Neurologic injuries in pelvic ring fractures

Unstable fractures of the pelvic ring are an increasingly frequent outcome of motor vehicle trauma. Neurologic injury after such injuries can be a cause of significant morbidity. The available literature on neurologic injuries was reviewed and compared with a clinical review of 90 unstable pelvic injuries treated during a 3-year period. Eighty-three patients were available for followup examination. Neurologic injuries were seen in 21 % of the patients. Thirty-seven percent of patients had sensory deficits alone whereas the remaining 63% had motor and sensory findings. All patients showed some evidence of neurologic recovery at an average or 24-months followup. At least 1 grade of muscle function improvement was consistently seen and 53% of patients had complete neurologic recovery. Improvement in function was seen as many as 24 months postinjury, but L5 function was least likely to progress to full recovery. The incidence of neurologic injuries and their distribution was similar to that reported in the literature, whereas the prognosis for neurologic recovery was significantly better. This may be related to techniques of early anatomic reduction and stabilization of unstable pelvic ring injuries.

Operative stabilization of fracture dislocations of the sacroiliac joint

Posterior fracture dislocations of the sacroiliac joint (crescent fracture) represent a subset of lateral compression pelvic fractures. The crescent fracture consists of a posterior iliac wing fracture with extension into the sacroiliac joint and a dislocation of the inferior 1/2 of the sacroiliac joint. The posterior superior iliac spine remains firmly attached to the sacrum by the strong posterior ligaments. As a result of this combination of bony and soft tissue injury, the hemipelvis is rotationally unstable, but because the sacrospinous and sacrotuberous ligaments remain intact the involved hemipelvis is stable to vertically applied forces. Operative stabilization is necessary to restore articular congruity of the sacroiliac joint, pelvic stability, and to allow early mobilization of the patient. Stabilization of the pelvis may be achieved through either an anterior or a posterior approach with or without transarticular fixation. A posterolateral approach to the crescent fracture and a method of stabilization using extraarticular fixation, intertable lag screws and outer table antiglide plates are described. The results of using this technique in 22 patients are reviewed.