Kristofer J. Jones

Neurophysiological detection of impending spinal cord injury during scoliosis surgery.

BACKGROUND Despite the many reports attesting to the efficacy of intraoperative somatosensory evoked potential monitoring in reducing the prevalence of iatrogenic spinal cord injury during corrective scoliosis surgery, these afferent neurophysiological signals can provide only indirect evidence of injury to the motor tracts since they monitor posterior column function. Early reports on the use of transcranial electric motor evoked potentials to monitor the corticospinal motor tracts directly suggested that the method holds great promise for improving detection of emerging spinal cord injury. We sought to compare the efficacy of these two methods of monitoring to detect impending iatrogenic neural injury during scoliosis surgery. METHODS We reviewed the intraoperative neurophysiological monitoring records of 1121 consecutive patients (834 female and 287 male) with adolescent idiopathic scoliosis (mean age, 13.9 years) treated between 2000 and 2004 at four pediatric spine centers. The same group of experienced surgical neurophysiologists monitored spinal cord function in all patients with use of a standardized multimodality technique with the patient under total intravenous anesthesia. A relevant neurophysiological change (an alert) was defined as a reduction in amplitude (unilateral or bilateral) of at least 50% for somatosensory evoked potentials and at least 65% for transcranial electric motor evoked potentials compared with baseline. RESULTS Thirty-eight (3.4%) of the 1121 patients had recordings that met the criteria for a relevant signal change (i.e., an alert). Of those thirty-eight patients, seventeen showed suppression of the amplitude of transcranial electric motor evoked potentials in excess of 65% without any evidence of changes in somatosensory evoked potentials. In nine of the thirty-eight patients, the signal change was related to hypotension and was corrected with augmentation of the blood pressure. The remaining twenty-nine patients had an alert that was related directly to a surgical maneuver. Three alerts occurred following segmental vessel clamping, and the remaining twenty-six were related to posterior instrumentation and correction. Nine (35%) of these twenty-six patients with an instrumentation-related alert, or 0.8% of the cohort, awoke with a transient motor and/or sensory deficit. Seven of these nine patients presented solely with a motor deficit, which was detected by intraoperative monitoring of transcranial electric motor evoked potentials in all cases, and two patients had only sensory symptoms. Somatosensory evoked potential monitoring failed to identify a motor deficit in four of the seven patients with a confirmed motor deficit. Furthermore, when changes in somatosensory evoked potentials occurred, they lagged behind the changes in transcranial electric motor evoked potentials by an average of approximately five minutes. With an appropriate response to the alert, the motor or sensory deficit resolved in all nine patients within one to ninety days. CONCLUSIONS This study underscores the advantage of monitoring the spinal cord motor tracts directly by recording transcranial electric motor evoked potentials in addition to somatosensory evoked potentials. Transcranial electric motor evoked potentials are exquisitely sensitive to altered spinal cord blood flow due to either hypotension or a vascular insult. Moreover, changes in transcranial electric motor evoked potentials are detected earlier than are changes in somatosensory evoked potentials, thereby facilitating more rapid identification of impending spinal cord injury.

Eleven years experience in the operative management of pediatric forearm fractures.

Background There has been a trend toward operative management of pediatric diaphyseal forearm fractures (DFFx). We studied our experience with surgical management of these injuries to assess indications, frequency, outcome, and complications. Methods One hundred forty-four consecutive children had surgical management of 149 DFFx over 11 years at our Level 1 pediatric trauma center. A chart/radiographic review established perioperative events, intraoperative findings, time-to-union, range-of-motion, and complications. We developed the Childrens Hospital of Philadelphia Forearm Fracture Fixation Outcome Classification to assess postoperative outcomes. Results Over 11 years, we treated 2297 DFFx; 155 of 2297 (6.7%) had surgical management. Six were lost to follow-up and excluded. A 7-fold increase in operative management was observed over the study period [2 of 143 (1.4%) vs. 28 of 270 (10.4%), P<0.001]. One hundred and three of 149 (69.1%) were treated with intramedullary nailing (IMN); 44 of 149 (29.5%) with plates; and 2 of 149 (1.3%) had combined plate/nail fixation. Thirty of 103 (29.1%) had the fracture site opened to pass the IMN; in 23 cases, open fractures were exploited to assist nail passage. When managed with IMN, open fracture sites showed slowed healing: union was 8.6 weeks for those opened intraoperatively and 6.9 weeks for those remaining closed (P<0.001). Fractures opened secondary to injury achieved union at 9.75 weeks which was significantly longer than those opened intraoperatively (8.6 wk, P=0.04) and those remaining closed (6.9 wk, P=0.001). Compartment syndrome occurred in 6.7% (2 of 30) treated with IMN within 24 hours of injury versus 0 of 73 treated later (P=0.026). Delayed union after IMN occurred in 6 children 10 years of age versus none less than 10 years of age. Poor/fair outcome of IMN increased with age [6 of 47 (13%) ≤10 y of age, vs. 17 of 56 (30%)>10 y of age, P=0.03]. Overall complication rate for IMN was 14.6% (15 of 103). Conclusions Our center has operatively managed DFFx with increased frequency over the past decade. IMN had a complication rate of 14.6% and was frequently not “minimally invasive.” An open fracture site delayed healing. Compartment syndrome was more frequent when IMN was used the day of injury and older children had poorer outcomes and higher rates of delayed union. Level of Evidence Level III, Retrospective Comparative Study.

The docking technique for lateral ulnar collateral ligament reconstruction: surgical technique and clinical outcomes

HYPOTHESIS Lateral ulnar collateral ligament (LUCL) reconstruction is a commonly used surgical approach for the treatment of posterolateral rotatory instability (PLRI). We hypothesized that favorable clinical results could be obtained using the docking technique. MATERIALS AND METHODS Between 1996 and 2009, the docking technique was used for surgical reconstruction of the LUCL in 8 patients with purely ligamentous posterolateral rotatory instability of the elbow. The clinical results of these patients were retrospectively reviewed. RESULTS At a mean follow-up of 7.1 years (range, 5.2-9.4 years), 6 patients (75%) demonstrated complete resolution of lateral elbow instability, and 2 (25%) reported occasional instability with activities of daily living. The mean Mayo Elbow Performance Score was 87.5 (range, 75-100). Subjective assessment revealed that all patients were satisfied with their clinical outcome. CONCLUSION LUCL reconstruction using the docking technique facilitates simple graft tensioning and excellent graft fixation. Clinical results are comparable with previously reported studies with a low complication rate.

Reverse total shoulder arthroplasty: Current concepts, results, and component wear analysis

After its introduction in the 1970s, reverse total shoulder arthroplasty had minimal clinical success, as its constrained design and lateralized glenohumeral center of rotation led to excessive shear forces and failure of the glenoid component1,2. Modern implant design modifications have emphasized a larger radius of curvature of the glenoid component and movement of the center of shoulder rotation medially and distally, creating a more stable and efficient fulcrum and decreasing shear forces at the glenoid-bone interface3,4. Since receiving U.S. Food and Drug Administration (FDA) approval in 2003, reverse total shoulder arthroplasty has become popular for use for more than rotator cuff-tear arthropathy; its uses include treatment of failed conventional total shoulder arthroplasties, rheumatoid arthritis in patients with an irreparable cuff tear, proximal humeral tumors, and proximal humeral fractures with anterosuperior escape5,6. However, with major complication rates as high as 26%7, limited implant longevity, and a lack of long-term functional outcome data, concerns have continued about its widespread use2. ### Source of Funding There was no external funding source for this investigation. Without injury, the glenohumeral joint possesses remarkable mobility and is able to remain stable over the majority of an individual’s life span. While both static and dynamic restraints contribute to its stability, the glenohumeral joint lacks substantial intrinsic osseous constraints8,9. Although the glenoid and the humeral head have similar shapes, they differ substantially in size. Warner demonstrated that the spherical humeral head has an articular surface area of approximately 21 to 22 cm2, while that of the glenoid is 8 to 9 cm2, with a maximum contact area of only 4 to 5 cm2 between the two surfaces10. This limited contact area and the shallow glenoid …

Functional outcomes of early arthroscopic bankart repair in adolescents aged 11 to 18 years.

Recurrent shoulder instability can significantly affect a patients quality of life and place them at risk for extensive soft tissue and bony injury with repeated dislocations. Literature on the operative management of recurrent instability in pediatric patients is limited, as most studies include pediatric patients within a larger sample group comprised primarily of adults. The purpose of this paper was to investigate the role of early arthroscopic Bankart repair (ABR) after anterior shoulder dislocation or subluxation in a pure pediatric population. We retrospectively reviewed 32 consecutive ABRs in 30 pediatric patients. Sixteen shoulders failed initial nonoperative therapy before ABR, whereas surgical stabilization was the primary treatment in 16 shoulders after initial evaluation at our institution. There were 17 males and 13 females with an average age of 15.4 years (age range, 11-18 years). The average follow-up was 25.2 months. Functional outcomes were measured using the single assessment numerical evaluation (SANE) score. In the initial nonoperative group, the average SANE score was 92.2. There were 3 shoulder redislocations in 2 patients (18.75%). In the 16 shoulders treated with ABR as initial therapy, the average SANE score was 91.8, and there were 2 shoulder redislocations in 2 patients (12.5%). We conclude that primary ABR is an effective treatment of traumatically induced shoulder instability in pediatric patients. Primary ABR limits multiple recurring shoulder dislocations that hinder a patients quality of life and places them at risk for future negative sequelae.

Elbow Ulnar Collateral Ligament Reconstruction in Javelin Throwers at a Minimum 2-Year Follow-up

Background: There are several large series of outcomes after ulnar collateral ligament (UCL) reconstruction that have 1 or 2 javelin throwers included. To our knowledge, however, there are no reports that focus solely on the results of UCL reconstruction in this group of athletes. Hypothesis/Purpose: We hypothesize that by using modern UCL reconstruction techniques, javelin throwers can reliably expect to return to their sport. Additionally, we review the principles behind postoperative rehabilitation in these athletes, as it differs from the usual approach used with baseball players. Study Design: Case series; Level of evidence, 4. Methods: This was a retrospective review of 10 javelin throwers who underwent UCL reconstruction between 2006 and 2009 using the docking technique. There were 5 college and 5 high school javelin throwers. The average age was 18.5 years (range, 18-21 years). All patients, before being indicated for ligament reconstruction, failed a course of nonoperative management that included rest, physical therapy, and a structured attempt to return to throwing. Postoperatively, patients were evaluated using the Conway Scale and the Andrews-Timmerman Score. Results: Patients were evaluated at a minimum 2-year follow-up. The average follow-up was 28.9 months after surgery (range, 24-45 months). On the Conway Scale, 9 of the 10 players had excellent outcomes (90%). There was one fair (10%) outcome. Average time to return to previous level of competition was 15 months. The mean Andrews-Timmerman Score was 97 (range, 85-100). Overall, 100% (10/10) of the patients were subjectively satisfied with their clinical outcome. Conclusion: Similar to other overhand athletes with UCL insufficiency, javelin throwers can reliably expect to return to their previous level of play after surgical reconstruction. A thorough understanding of the unique demands placed on these athletes because of the different throwing motion is helpful when tailoring their postoperative rehabilitation protocol. Additionally, these athletes must be counseled that the postoperative course is associated with an extended period of time until return to previous level of competition when compared with baseball players.

Segmental contribution toward total lumbar range of motion in disc replacement and fusions: a comparison of operative and adjacent levels.

Study Design. Radiographic results from a prospective, randomized, multicenter trial assessing patients who underwent lumbar total disc replacement (TDR) or circumferential arthrodesis for 1-level degenerative disc disease. Objective. To quantify the relative segmental contribution to total lumbar range of motion (ROM) at the operative level at each adjacent level in lumbar TDR and arthrodesis. Summary of Background Data. Although previous studies have evaluated ROM in TDR and fusion, no study has quantified or compared the relative segmental contribution to total lumbar ROM. Further, no study to the best of our knowledge has evaluated the kinematic profile of the more cranial adjacent segments (i.e., the second or third adjacent levels) following implantation of either TDR or fusion. Methods. Radiographic data collected from all randomized 1-level degenerative disc disease patients operated at L4/5 or L5/S1 that participated in the multicenter, prospective, randomized IDE study comparing ProDisc-L with circumferential lumbar arthrodesis were evaluated before surgery and at 24 months. Radiographic measurements were performed independently using custom digitized image stabilization software to generate ROM at the operative level, and at each cranial and caudal adjacent level. Results. There were 200 total patients included (155 ProDisc-L, average age 39 years; 45 arthrodesis, average age 40 years). At 24 months, the L4/5 TDR group experienced a significant improvement in total lumbar ROM from baseline (+6.3°), whereas there was no change seen with L5/S1 TDR or any fusion group. Between-group comparisons from baseline to 24 months postoperatively revealed: (1) significantly more contribution from the operative level towards total lumbar range in TDR at operative level L4/5 (TDR: −2.5%, fusion: −16.8%, P = 0.006), and operative level L5/S1 (TDR: −5.1%, fusion: −15.9%, P < 0.001), and (2) the relative contribution towards total lumbar range of motion from the first cranial adjacent segment to fusion at L5/S1 increased by 12.1%, compared with −1.2% seen in TDR (P = 0.03). There were elevated contributions from the more cranial adjacent levels to a fusion when compared with TDR, however, these differences were not statistically significant. At operative level L4/5, there was significantly increased ROM from the first caudal segment below TDR (6%, P = 0.03), but not below fusion (3.1%, P = 0.59). Conclusion. In conclusion, patients with TDR lost slight relative contribution to total lumbar motion from the operative level which was mostly compensated for by the caudal adjacent level (if operated at L4/5). In contrast, the significant loss of relative range of motion contribution from the operative level in fusions was redistributed among multiple cranial adjacent levels, most notably at the first cranial adjacent level.

Functional outcomes following revision ulnar collateral ligament reconstruction in Major League Baseball pitchers

BACKGROUND There is a paucity of data regarding outcomes following revision ulnar collateral ligament (UCL) reconstruction in Major League Baseball (MLB) pitchers. A single case series comprised of 4 MLB pitchers has reviewed outcomes in this cohort and reported a 75% rate of return to pitching. We hypothesize that MLB pitchers demonstrate a low rate of return to their pre-injury pitch workload following revision surgery. METHODS Clinical outcomes were reviewed with an emphasis on return to pre-injury pitch workload. Utilizing MLB player performance statistics, the postoperative pitch workload (appearances for relief pitchers and games started/innings pitched for starting pitchers) was calculated to determine if players were able to resume pre-injury throwing activity. Position-specific analyses for pitchers (starter vs relief) were also performed utilizing objective pitching statistics. RESULTS Overall, 78% (14/18) of pitchers were able to return to MLB play within 2 full seasons. Relief pitchers were able to resume 50% of their pre-injury pitch workload, while starting pitchers only reached 35% of their prior workload (P = .52). Relievers demonstrated better pitching statistics (ERA [earned run average], K/9 [strikeouts per 9 innings], and BB/9 [walks per 9 innings]) when compared to starters. Two starting pitchers were reassigned to relief roles by their teams, resulting in improvement in their postoperative pitch workload (mean 94%). CONCLUSION The overall rate of return to pre-injury pitch workload following revision UCL reconstruction is low among professional pitchers. Starting pitchers may be at higher risk for treatment failure in the revision setting, given the increased demands of the position, and may benefit from reassignment to a relief role.

Operative Management of Ulnar Collateral Ligament Insufficiency in Adolescent Athletes

Background: The incidence of ulnar collateral ligament (UCL) injuries of the elbow has increased in adolescents over the past decade because of widespread participation in athletics and heightened awareness among physicians. Hypothesis: Ulnar collateral ligament reconstruction using the docking technique would result in a successful return to athletic activity in this age group. Study Design: Case series; Level of evidence, 4. Methods: Study participants were 55 skeletally mature adolescent athletes (mean age, 17.6 years; range, 15-18 years) who underwent UCL reconstruction between 2008 and 2010. While the majority of patients were baseball players (n = 47), there were 3 gymnasts and 5 javelin throwers included in the study. Each patient underwent UCL reconstruction utilizing the docking technique after an adequate trial of nonoperative management (mean, 5.8 months). At the latest follow-up, patients were evaluated to determine their ability to return to athletic activity. Clinical outcomes were classified using the Conway scale, the Andrews-Timmerman score, and the Kerlan-Jobe Orthopaedic Clinic (KJOC) score. Results: At a minimum 2-year follow-up, 87% (48/55) of patients had excellent results using the Conway scale. Overall, there were only 2 poor results (3.6%) that were observed in patients with concomitant osteochondritis dissecans lesions of the capitellum. There were 4 postoperative complications in 4 patients (2 gymnasts and 2 javelin throwers) who developed ulnar neuritis after UCL reconstruction. The mean Andrews-Timmerman score was 83.6 ± 7.2 (range, 30-100), and the mean KJOC score was 88.0 ± 6.0 (range, 40-100). Conclusion: The docking technique results in favorable clinical outcomes in adolescent athletes with UCL insufficiency at a minimum of 2 years postoperatively. Patients with concomitant intra-articular lesions should be cautioned preoperatively that they might experience inferior clinical outcomes. Postoperatively, adolescent gymnasts and javelin throwers may be at an increased risk for transient paresthesia of the ulnar nerve caused by increased stress on the medial elbow.

Arthroscopic Management of Osteochondritis Dissecans of the Capitellum: Mid-term Results in Adolescent Athletes

Background The optimal treatment of osteochondritis dissecans (OCD) of the capitellum in adolescent athletes remains challenging. The purpose of this study was to investigate the mid-term results of arthroscopic treatment of OCD of the capitellum in a series of adolescents. Methods We identified 25 consecutive patients at our institution that underwent arthroscopic treatment for OCD of the capitellum since 1999. Ten elbows were treated by arthroscopic debridement and drilling alone, whereas 12 elbows required additional mini-arthrotomies for bone grafting or the removal of large loose bodies after arthroscopy. The clinical charts and operative reports of these patients were retrospectively reviewed for relevant clinical information including age, sport, character of symptoms, preoperative and postoperative range of motion, return to sport, and postoperative complications. Twenty-one patients (22 elbows) were reached to determine their current elbow function and athletic activity using the Single Assessment Numerical Evaluation score. Results The average age of the patients in our series was 13.1 years. All patients participated in organized athletics that involved the upper extremity and had undergone an average of 10.2 months of nonoperative treatment before surgery. At a mean follow-up of 48 months, the patients gained an average of 17 degrees of extension and 10 degrees of flexion after surgery. Both the improvement in flexion and extension were statistically significant compared with the preoperative range of motions (P=0.001, P=0.01). When patients were asked to rate their elbow function from 0% to 100% using the Single Assessment Numerical Evaluation score, the average rating was 87%. Eighteen of 21 patients (86%) returned to participate in their sport at their preinjury level. Conclusion Arthroscopic management of capitellar OCD in adolescent athletes results in significantly improved range of motion and a high rate of return to athletics. Accompanying arthrotomy may be required for large loose body removal or bone grafting. Level of Evidence Level IV (case series).