Indirect decompression of lumbar stenosis with transpsoas interbody cages and percutaneous posterior instrumentation.

BACKGROUND: The minimally invasive lateral transpsoas retroperitoneal approach to address lumbar stenosis offers advantages to traditional approaches, including sparing of the AP annulus and longitudinal ligament and less risk to the peritoneal contents and retroperitoneal vascular structures. Few studies have presented longitudinal measures of radiographic indirect decompression and relief of pain and restoration of function using the lateral approach to spine fusion. QUESTION/PURPOSES: We determined (1) whether radiographic measures suggestive of decompression were achieved after surgery and maintained 1 year after surgery, (2) whether the intervention resulted in sustained improvements in patient-reported outcomes scores 1 year after surgery, and (3) the frequency of pseudarthrosis on CT scans at 1 year after surgery in patients with moderate or severe lumbar stenosis treated with the approach. METHODS: Between 2008 and 2012, 158 patients were surgically treated to alleviate symptoms associated with degenerative lumbar stenosis, of whom 60 (38%) were treated with lateral lumbar interbody fusion. Of these 60 patients, 36 (60%) received CT scans preoperatively and at 1-year postoperatively and were available for radiographic analysis. Of the 60 treated patients, 16 (27%) were lost to followup before 12 months, leaving the records of 44 patients available for review of patient-reported improvements in pain and return to function. Radiographic increases in disc height, foraminal area, and canal area were measured by one observer on CT scans postoperatively and at 1 year and compared to preoperative values. Patient-reported scores, including VAS pain score and Oswestry Disability Index (ODI), were collected preoperatively and at 3 and 12 months postoperatively. RESULTS: Increases in disc height (67%, p < 0.001), foraminal area (24%-31%, p < 0.001), and canal area (7%, p = 0.011) measured immediately postoperatively were sustained at 1-year followup. VAS pain score and ODI both improved (p < 0.001) at 3 months and were maintained at 1 year. No pseudarthroses were noted radiographically. CONCLUSIONS: The lateral transpsoas approach to interbody fusion is capable of sustaining indirect decompression of the neural structures and resolving preoperative claudication and radiculopathy. A larger series of patients with longer followup should be studied to substantiate these early clinical results. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

A cadaveric radiographic analysis on the effect of extreme lateral interbody fusion cage placement with supplementary internal fixation on indirect spine decompression.

STUDY DESIGN: Cadaveric Biomechanical and Radiographic Analysis. OBJECTIVE: The purpose of this study was to quantify the changes in intervertebral height and lateral and central recess areas afforded by lateral interbody fusion cages with 2 supplemental forms of internal fixation in cadaveric specimens. BACKGROUND DATA: When conservative treatment for symptomatic lumbar stenosis fails, traditional intervention has been direct posterior decompression. The minimally invasive, lateral transpsoas approach may be a viable alternative to direct decompression by providing restoration of the foraminal and intervertebral dimensions, yet few reports have examined the anatomic and radiographic changes that occur using this technique. METHODS: Computed tomography (CT) scans were taken of 18 intact lumbar (L1-S1) cadaveric specimens under a 400 N preload. Intervertebral height, foraminal areas, and canal area were measured at L3-L4 and L4-L5. Thereafter, the cadaveric specimens were instrumented with lateral cages placed in the central or posterior third of the disk space at L3-L4 and L4-L5 and either (1) lateral plate (n=9) or (2) bilateral posterior pedicle screw fixation (n=9). All constructs were again subjected to a 400 N preload, postinstrumentation CT scans were taken, and changes in intervertebral height and lateral and central recess areas were calculated. RESULTS: There was no effect of cage placement on any radiographic metric of indirect decompression for either fusion construct. In the lateral plate and pedicle screw groups, respectively, significant increases in average posterior disk height (30.9%, 60.1%), average right (35.3%, 61.5%) and left foraminal area (48.3%, 57.8%), and average canal area (32.3%, 33.3%) were observed. Pedicle screw instrumentation afforded a significantly greater increase in average posterior disk height and foraminal area compared with the lateral plate group, though there was no difference in the average increase in canal area afforded by either form of fixation. CONCLUSIONS: The radiographic results reported here using a cadaveric model add validity to the underlying rationale described for the minimally invasive lateral approach technique. Increases in disk height, foraminal and canal areas were not dependent on cage positioning within the disk space. As intraoperative placement of a cage in the central portion of the disk is an easier and safer technique, our results suggest that central placement may be preferable in a clinical setting.

Effects on inadvertent endplate fracture following lateral cage placement on range of motion and indirect spine decompression in lumbar spine fusion constructs: A cadaveric study.

BACKGROUND: The lateral transpsoas approach to interbody fusion is gaining popularity. Existing literature suggests that perioperative vertebra-related complications include endplate breach owing to aggressive enedplate preparation and poor bone quality. The acute effects of cage subsidence on stabilization and indirect decompression at the affected level are unknown. The purpose of this study was to compare the kinematics and radiographic metrics of indirect decompression in lumbar spines instrumented with laterally placed cages in the presence of inadvertent endplate fracture, which was determined radiographically, to specimens instrumented with lateral cages with intact endplates. METHODS: Five levels in 5 specimens sustained endplate fracture during lateral cage implantation followed by supplementary fixation (pedicle screw/rod [PSR]: n = 1; anterolateral plate [ALP]: n = 4), as part of a larger laboratory-based study. Range of motion (ROM) in these specimens was compared with 13 instrumented specimens with intact endplates. All specimens were scanned using computed tomography (CT) in the intact, noninstrumented condition and after 2-level cage placement with internal fixation under a 400-N follower load. Changes in disc height, foraminal area, and canal area were measured and compared between specimens with intact endplates and fractured endplates. RESULTS: Subsidence in the single PSR specimen and 4 ALP specimens was 6.5 mm and 4.3 ± 2.7 mm (range: 2.2-8.3 mm), respectively. ROM was increased in the PSR and ALP specimens with endplate fracture when compared with instrumented specimens with intact endplates. In 3 ALP specimens with endplate fracture, ROM in some motion planes increased relative to the intact, noninstrumented spine. These increases in ROM were paralleled by increase in cage translations during cyclic loading (up to 3.3 mm) and an unpredictable radiographic outcome with increases or decreases in posterior disc height, foraminal area, and canal area when compared with instrumented specimens with intact endplates. CONCLUSIONS: Endplate fracture and cage subsidence noted radiographically intraoperatively or in the early postoperative period may be indicative of biomechanical instability at the affected level concomitant with a lack of neurologic decompression, which may require revision surgery.

Hip abductor moment arm--a mathematical analysis for proximal femoral replacement.

BACKGROUND: Patients undergoing proximal femoral replacement for tumor resection often have compromised hip abductor muscles resulting in a Trendelenberg limp and hip instability. Commercially available proximal femoral prostheses offer several designs with varying sites of attachment for the abductor muscles, however, no analyses of these configurations have been performed to determine which design provides the longest moment arm for the hip abductor muscles during normal function. METHODS: This study analyzed hip abductor moment arm through hip adduction and abduction with a trigonometric mathematical model to evaluate the effects of alterations in anatomy and proximal femoral prosthesis design. Prosthesis dimensions were taken from technical schematics that were obtained from the prosthesis manufacturers. Manufacturers who contributed schematics for this investigation were Stryker Orthopaedics and Biomet. RESULTS: Superior and lateral displacement of the greater trochanter increased the hip abductor mechanical advantage for single-leg stance and adduction and preserved moment arm in the setting of Trendelenberg gait. Hip joint medialization resulted in less variance of the abductor moment arm through coronal motion. The Stryker GMRS endoprosthesis provided the longest moment arm in single-leg stance. CONCLUSIONS: Hip abductor moment arm varies substantially throughout the hip's range of motion in the coronal plane. Selection of a proximal femur endoprosthesis with an abductor muscle insertion that is located superiorly and laterally will optimize hip abductor moment arm in single-leg stance compared to one located inferiorly or medially.

Enhancing soft tissue ingrowth in proximal femoral arthroplasty with aortograft sleeve: a novel technique and early results.

Hip abductor function is critical to joint stability after proximal femoral arthroplasty. Normal soft tissue relationships are often violated during this procedure for complete tumor resection. Abductor insufficiency leads to abnormal gait mechanics and poor function. To improve soft tissue stability about a metallic proximal femoral endoprosthesis, we devised a novel use of vascular graft material. Two patients received a proximal femoral arthroplasty using this technique. These patients were followed for an average of 26.5 months. They demonstrated mean active hip abduction of 48°, hip flexion of 90°, mean Musculoskeletal Tumor Society score of 24 (80%), and Toronto Extremity Salvage Score of 80. We believe that this technique may be useful in achieving soft tissue stability about a metal endoprosthesis and may facilitate better function in patients undergoing this surgery.

What is the emotional acceptance after limb salvage with an expandable prosthesis?

BACKGROUND: Limb preservation surgery for extremity sarcomas offers the promise of improved function and cosmesis over amputation. Application of limb salvage surgery for pediatric patients with expandable metallic endoprostheses is gaining acceptance. The few studies reporting these devices have focused on functional outcomes; one has addressed quality of life. QUESTIONS/PURPOSES: We asked the following questions: (1) how happy are these patients; (2) how do these patients perceive their bodies; (3) do these children have difficulty with social interactions; and (4) how satisfied are patients and their parents with their outcomes? METHODS: We retrospectively identified and contacted 26 living patients who underwent limb salvage with an expandable device. The Pediatric Outcomes Data Collection Instrument was administered to 15 of the 26 families. Attention was paid to the happiness domain of the Pediatric Outcomes Data Collection Instrument and specific answers within this domain were reported. RESULTS: Children who received limb salvage with an expandable endoprosthesis showed high emotional satisfaction with their outcome. Overall patients reported excellent perceptions of body image and physical attractiveness. Most patients reported frequent social interactions with their peers and no difficulty with making new friends. CONCLUSIONS: Although this study has a limited number of subjects and no control group, the data correlate with previously scores and indicate a high degree of emotional acceptance after limb salvage with an expandable endoprosthesis in a pediatric population.

Proximal and total humerus reconstruction with the use of an aortograft mesh.

BACKGROUND: The shoulder is commonly affected by primary and metastatic tumors. Current surgical techniques for complex shoulder reconstruction frequently result in functional deficits and instability. A synthetic mesh used in vascular surgery has the biological properties to provide mechanical constraint and improve stability after tumor related shoulder reconstruction. QUESTIONS/PURPOSES: We describe (1) surgical technique using a synthetic mesh during humerus reconstructions; (2) functional level defined as shoulder ROM of patients undergoing the procedure; (3) incidence of postoperative dislocation and shoulder instability; and (4) complications associated with the use of the device. METHODS: We retrospectively reviewed 16 patients with proximal humerus replacements reconstructed with a synthetic mesh from February 2006 to July 2008. Patients were followed clinically and radiographically for a minimum of 13 months (mean, 26 months; range, 13-43 months). RESULTS: There were no shoulder dislocations at the latest followup. The mean shoulder flexion was 43° (range, 15°-170°) and mean shoulder abduction of 38 (range, 15°-110°). The mean operative time was 121 minutes (range, 80-170 minutes) and the mean blood loss was 220 mL (range, 50-750 mL). One patient had a superficial wound infection and none a deep infection requiring removal of the graft or prosthesis. CONCLUSIONS: The data suggest the use of a synthetic vascular mesh for proximal humerus reconstruction may reduce dislocations and facilitate soft tissue attachment and reconstruction after tumor resection.

Percutaneous drilling for the treatment of atraumatic osteonecrosis of the ankle.

Atraumatic osteonecrosis of the ankle can be severely debilitating and can lead to joint collapse. A relatively new technique of percutaneous drilling has previously been used to relieve the symptoms of osteonecrotic hips and knees. The purpose of the present study was to examine the results of this technique when used to treat osteonecrosis of the ankle. Between September 2002 and June 2005, the senior author (M.A.M.) treated and prospectively followed 44 symptomatic osteonecrotic ankles (31 patients) using this drilling technique. The series included 23 (74.2%) women and 8 (25.8%) men with a mean age of 43 +/- 11 years. Arthrodesis had been recommended for 14 (45.2%) of these patients (20 [45.5%] ankles). At a mean follow-up duration of 45 +/- 12 months, 40 (91%) ankles had achieved a successful clinical outcome. The mean American Orthopaedic Society of Foot and Ankle Society Ankle and Hindfoot score increased from 42 +/- 5 points preoperatively to 88 +/- 10 points postoperatively, and this difference was statistically significant (P < .0001). There were no perioperative complications, although 3 ankles subsequently collapsed and required arthrodesis. The percutaneous drilling technique appears to be a useful method for the relief of symptomatic ankle osteonecrosis.

Purse-string capsule repair to reduce proximal femoral arthroplasty dislocation for tumor--a novel technique with results.

Hip joint dislocation is the most common complication after proximal femoral arthroplasty with a large endoprosthesis. Average dislocation rates are around 15%. In an attempt to decrease dislocations after proximal femoral arthroplasty for tumor resections, we devised a novel closure of the hip capsule. This technique uses a 3-mm cottony Dacron suture placed about the hip capsule in a circumferential, purse-string manner. Thirty-nine patients received hip hemiarthroplasty with purse-string capsular closure. Seven patients were lost to follow-up, leaving 36 patients available for analysis. One patient dislocated (2.8%). We believe this technique is useful in preventing dislocation in patients undergoing proximal femoral arthroplasty for oncologic disease.

Static progressive stretch improves range of motion in arthrofibrosis following total knee arthroplasty.

Arthrofibrosis is a relatively common complication after total knee arthroplasty that negatively affects function and quality of life. Static progressive stretching is a technique that has shown promising results in the treatment of contractures of the elbow, ankle, wrist and knee. This study evaluated a static progressive stretching device as a treatment method for patients who had refractory knee stiffness after total knee arthroplasty. Twenty-five patients who had knee stiffness and no improvement with conventional physical therapy modalities were treated with the device. After a median of 7 weeks (range, 3-16 weeks), the median increase in range of motion was 25 degrees (range, 8-82 degrees). The median gain in knee active flexion was 19 degrees (range, 5-80 degrees). Ninety-two percent of patients were satisfied with the results. The authors believe static progressive stretching devices may be an effective method for increasing the ranges of motion and satisfaction levels of patients who develop arthrofibrosis after total knee arthroplasty.

Small-diameter percutaneous decompression for osteonecrosis of the shoulder.

Core decompression of the humeral head has previously been used as a joint-preserving procedure for treatment of symptomatic osteonecrosis of the shoulder. In this article, we describe a new decompression technique, which involves multiple small-diameter (3-mm) percutaneous perforations. In our study population (early-stage disease), shoulder arthroplasty was avoided in all 15 patients (26 shoulders) for a mean follow-up of 32 months (range, 24-41 months). Of the 26 shoulders, 25 had successful clinical and functional outcomes (University of California Los Angeles shoulder score, >24 points), and 1 showed radiographic progression of the disease but has not needed further operative treatment. We compared our decompression results with those of a nonoperative historical control group, identified through a literature search. There was a 48% (143/299) rate of progression to arthroplasty in the control group at a follow-up ranging from 2 to 4.5 years. This outpatient, percutaneous perforations technique appears to be a low-morbidity method for relieving symptoms and deferring shoulder arthroplasty in patients with symptomatic osteonecrosis of the humeral head.

Perioperative management for orthopaedic patients with sickle cell anaemia.

PURPOSE: To compare outcomes of 2 types of perioperative optimisation for patients with sickle cell anaemia (SCA) undergoing various orthopaedic surgeries. METHODS: 12 female and 11 male patients aged 13 to 40 (mean, 18) years with SCA underwent 31 separate orthopaedic procedures for osteonecrosis of the femoral head. They were referred to a haematologist for 2 types of perioperative optimisation, based on the choice of the attending paediatrician. In the aggressive management group, patients received packed red blood cells preoperatively to increase the haemoglobin level to 9 to 11 g/dl and to lower the haemoglobin S level to <30%. Fresh frozen plasma was given when their Factor VII level was <30%. In the conservative management group, patients received packed red blood cells preoperatively to increase the haemoglobin level to a minimum of 10 g/dl. Fresh frozen plasma or packed red blood cells were given intra-operatively only when excessive bleeding occurred. The length of hospital stay, the number of perioperative complications, the number of transfusions, and episodes of alloimmunisation and/or vaso-occlusive crises in the two groups were compared. RESULTS: No patient in the aggressive management group received supplemental oxygen or had an estimated intra-operative blood loss of >400 ml. Three patients in the conservative management group received multiple intra- and post-operative transfusions and supplemental oxygen. CONCLUSION: Both aggressive and conservative protocols may be safely used in SCA patients. The more aggressive protocol resulted in lower rates for postoperative complications, transfusions, and resorting to supplemental oxygen.

Hemostasis using a bipolar sealer in primary unilateral total knee arthroplasty.

Previous studies have shown that, compared with standard electrocautery, a bipolar sealer reduces tissue damage and smoke production during surgery. We conducted a multicenter, prospective, randomized study to compare a bipolar sealer with standard electrocautery for hemostasis. Sixty-nine primary total knee arthroplasties were performed. Cohorts were evaluated for intraoperative and postoperative blood loss, blood transfusion requirements, postoperative hemoglobin and pain levels, length of hospital stay, range of motion, and Knee Society scores. Amount of blood loss and decrease in postoperative hemoglobin were significantly lower in the bipolar sealer group than in the standard electrocautery group. Need for autologous blood transfusions was decreased in the bipolar sealer group compared with the electrocautery group. There were no between-groups differences in clinical knee scores. The bipolar sealer was an effective coagulation alternative for total knee arthroplasties in reducing blood loss and transfusion requirements without affecting clinical outcome.

Orthopedic surgery implications of breast cancer.

Breast cancer is the most common malignancy and the second leading cause of death in women. The metastatic involvement of bone denotes disease progression and decreased survival. Controversy exists regarding the exact pathophysiologic mechanism of metastasis and the different pathways that determine an osteoblastic versus osteoclastic bone compromise. Several breakthrough advances in imaging techniques aid in the detection, staging and follow-up of bone metastases. Although usually responsive to hormonal therapy and pharmacologic interventions, skeletal metastases often require some type of surgical intervention. Orthopedic surgeons should establish an active role in the multidisciplinary treatment of patients with breast cancer.

Use of extendable prostheses: a limb-salvaging alternative for patients with malignant bone tumors.

Children with primary bone tumors require radical surgical procedures and complex reconstructions. In addition to adequate disease control, the surgeon has to address the injured growth plate and consequent limb length inequality. Extendable prostheses constitute an alternative to other limb-salvaging techniques. Since the first description of the device three decades ago, several changes in materials, design and indications have been a matter of constant debate. The indications and results of this prosthesis will be reviewed and an expert commentary regarding the current and future trends of the device will be presented.

Reductions in blood loss with a bipolar sealer in total hip arthroplasty.

Altogether, 50 primary total hip arthroplasties were performed in a prospective, blinded, randomized study comparing a bipolar sealer device to standard electrocautery for hemostasis. Cohorts were evaluated for intra- and postoperative blood loss, transfusion rate, hemoglobin levels and modified Harris hip scores. Variables such as age, gender and body mass index were correlated to transfusion requirements. Total blood loss in the bipolar sealer group was decreased by 40% and transfusions were reduced by 73%. There was a significant reduction in the intra- and postoperative blood loss, p = 0.002 and p = 0.001, respectively. There was no difference in clinical hip scores between groups. The bipolar sealer was an effective coagulation alternative for total hip arthroplasties, reducing blood loss and transfusion requirements without affecting outcome. It appears to reduce tissue damage and smoke production in comparison with standard electrocautery. These results were found even in patients with demographic characteristics associated with a higher risk of blood-related complications.

Orthopedic surgery options for the treatment of primary osteosarcoma.

BACKGROUND: Osteosarcoma is the most common malignant primary neoplasm of bone. Orthopedic procedures are essential components in the multidisciplinary treatment of osteosarcoma. Limb-salvaging procedures offer adequate disease control comparable to the results obtained by amputations. This review discusses the advantages and disadvantages of the various types of amputations and the limb-salvaging techniques for the treatment of osteosarcoma. METHODS: The authors analyzed the characteristics of limb-salvaging procedures and amputations for osteosarcoma. Qualitative and quantitative studies published in the English language that are listed in the National Library of Medicine were used as the basis for this review. In addition, a review of an expandable prosthesis is included. RESULTS: Limb-salvaging techniques have acceptable rates of disease control. However, amputation remains a valid procedure in selected cases of osteosarcoma in most parts of the world. Orthopedic oncology surgeons have various materials, procedures, and techniques available to achieve disease control and improve function in patients with osteosarcoma. CONCLUSIONS: The surgical management of patients with osteosarcoma is challenging. No difference in survival has been shown between amputations and adequately performed limb-salvaging procedures. Optimal tumor resection and a functional residual limb with increased patient survival are the goals of modern orthopedic oncology.

Early clinical experience with the use of the Birmingham hip resurfacing system.

This study reviews the early clinical experience with the Birmingham Hip resurfacing system (Smith & Nephew, Memphis, Tenn) in the United States since its approval by the FDA. A total of 230 patients were followed for a mean of 16 months (range, 6 months). There was a significant improvement in the mean preoperative Oxford hip score at the latest follow-up (44 points [range, 30-58 points] to 17 points [range, 12-28 points]). The most commonly used femoral component was 50 mm, and the mean duration of the procedures was 95 minutes (range, 65-180 min). there were 3 revisions (1.3%). Early results are favorable. As with any device, there is a continuing need for longterm monitoring and large-scale epidemiologic surveillance.

Resurfacing for Perthes disease: an alternative to standard hip arthroplasty.

Metal-on-metal total hip resurfacing is an alternative to conventional total hip arthroplasty with several reports describing the benefits of this procedure in young patients. We retrospectively compared the clinical (including range-of-motion and leg length restoration) and radiographic outcome of resurfacing in young patients with Legg-Calvé-Perthes to those of patients of a similar age treated with a standard total hip arthroplasty. Eighteen patients (19 hip resurfacings) who had a mean age of 33 years (range, 18-34 years) were followed for a minimum of 26 months (mean, 51 months; range, 26-72 months). We used an anterolateral approach in four hips and a posterior approach with a trochanteric advancement in 15 hips. Eighteen of the 19 hips had Harris hip scores greater than 80 points at final followup. All patients improved range of motion while avoiding any clinically apparent impingement. Leg length was gained in 16 hips where preoperative measurements were available. The short-term results of hip resurfacing for the treatment of Perthes disease compare similarly to those found in the literature for standard total hip arthroplasty in young patients. The trochanteric advancement technique described may aid in treating the deformed femoral anatomy.