Quantification of Increase in Three-dimensional Spine Flexibility Following Sequential Ponte Osteotomies in a Cadaveric Model.

BACKGROUND: Posterior-only procedures are becoming more popular for treatment of rigid adolescent idiopathic scoliosis, but little is known about the quantitative correction potential for Ponte osteotomies. The objective of this study was to quantify and compare the range of motion of intact multilevel thoracic spine segments with the same segments after each of 3 sequential Ponte osteotomies. METHODS: We tested 5 human cadaveric thoracic spine segments, spanning T-T6, or T7-T12, in an 8-degree-of-freedom servo-hydraulic load frame, monitoring motion of each vertebra with an optical motion tracker. We measured range of motion while we applied cyclic, pure moment loading to produce flexion-extension, lateral bending, and axial rotation at a rate of 0.5°/second, to a maximum of ± 6 Nm. Each specimen was tested intact and after each of 3 sequential Ponte osteotomies. RESULTS: Total range of motion for the segments (either T2-T5 or T8-T11) increased by as much as 1.6° in flexion, 1.5° in extension, 0.5° in lateral bending, and 2.8° in axial rotation with each osteotomy. Because of the variation in initial specimen stiffness, we normalized motions to the intact values. In flexion, average range of motion increased after each osteotomy compared with intact, by 33%, 56%, and 69%. In extension, slightly smaller increases were seen, increasing by as much as 56% after the third osteotomy. In lateral bending, Ponte osteotomies had little effect on range of motion. In axial rotation, range of motion increased by 16%, 29%, and 65% after 3 osteotomies. CONCLUSIONS: Sequential Ponte osteotomies increased range of motion in flexion, extension, and axial rotation, but not in lateral bending. These results suggest that the Ponte osteotomy may be appropriate when using derotational correction maneuvers, or to improve apical lordosis at the apex of curvature during posterior spinal fusion procedures. Although these techniques are effective in gaining correction for kyphotic deformities and rigid curvatures, they add time and blood loss to the procedure.

Treatment of idiopathic clubfoot: experience with the Mitchell-Ponseti brace.

OBJECTIVE: The Mitchell-Ponseti (MP) foot abduction orthosis was introduced to provide a more user-friendly alternative to the traditional Denis-Browne (DB) brace in the treatment of idiopathic clubfoot. We describe our experience with the effectiveness of the MP brace to maintain correction of clubfeet corrected using the Ponseti method. METHODS: We evaluated 57 consecutive infants with 84 idiopathic clubfeet who were treated using the Ponseti method. After initial correction of the deformity was obtained, all infants were placed in the MP brace. RESULTS: The patients were followed for a minimum of 2 years (mean, 37.9 mo; range, 24 to 56 mo). Seventy-nine feet (94%) had heel-cord tenotomy or lengthening. The families of 34 (60%) patients were adherent with the postcorrective brace protocol. Skin problems were observed in 8 patients (14%), 6 of which were superficial dorsal skin abrasion, and none of the sandals required customization by an orthotist. A recurrence occurred in 40 feet (48%). Correction was regained with manipulation and cast application in all cases. Nineteen feet (23%) in 14 patients have had, or are scheduled for, an anterior tibial tendon transfer. At latest follow-up, all feet were plantigrade and had at least 10 degrees of dorsiflexion. None of the patients required surgical releases. Of 31 patients followed for at least 3 years, 26 (84%) used the brace for a minimum of 3 years. CONCLUSIONS: Using the MP foot abduction orthosis, we were able to achieve compliance rates that were at least comparable with those of earlier reports using the DB brace. Families found the brace easy to use. The MP brace may be considered a useful alternative to the DB brace. LEVEL OF EVIDENCE: Level II--prospective.

Triple arthrodesis with lateral column lengthening for the treatment of planovalgus deformity.

BACKGROUND: The rigid planovalgus foot has historically been difficult to correct and maintain in a corrected position with triple arthrodesis (TA). The lateral column lengthening (LCL) is a procedure that corrects the position of the planovalgus foot. Combining the TA with LCL at the calcaneocuboid joint may improve ultimate position after fusion for patients with rigid planovalgus foot deformities. METHODS: A retrospective review of all patients who underwent TA with LCL through the calcaneocuboid joint for rigid planovalgus foot deformity was performed. Preoperative and postoperative radiographs were compared for foot alignment by measuring the talo-first metatarsal angle in the anterior-posterior and lateral planes, calcaneal pitch, talo-horizontal angle, metatarsal stacking angle, and medial/lateral column ratio. Clinical outcomes were evaluated for correlation with preoperative and postoperative deformity and surgical indications. RESULTS: were evaluated using radiographic and clinic outcome measures developed for TA and LCL. RESULTS: : Twenty-nine surgeries were identified with solid fusions occurring in 27 patients by 12 weeks postoperatively. Two patients with cerebral palsy had persistent hindfoot valgus. At an average follow-up of 32 months after surgical intervention, correction of the talo-first metatarsal angle in the AP and lateral planes, calcaneal pitch, and talo-horizontal angles were statistically significant. There were 25 good clinical results with minimal or no pain with activity (86.2%) and 4 poor or fair results with moderate or severe pain (13.8%). There were 26 radiographic successes (89.7%) and 3 radiographic failures (10.3%). Cerebral palsy was associated with a higher rate of radiographic failures (P=0.01). There were 15 total complications in 11 feet (37.9%). These included 4 related to hardware, 3 involving neurological symptoms, 2 related to soft tissues, development of a symptomatic bony prominence in 2 patients, 1 forefoot deformity, 2 nonunions, and 1 case of Achilles tendonitis. CONCLUSION: Good correction can be obtained and maintained with LCL and TA for rigid planovalgus foot deformity. The procedure is associated with good short-term clinical and radiographic outcomes and improves the position of the foot with diminished risk of recurrent or continued deformity as compared with historical controls. LEVEL OF EVIDENCE: Level IV (case series).

VEPTR™ growing rods for early-onset neuromuscular scoliosis: feasible and effective.

BACKGROUND: The Vertical Expandable Prosthetic Titanium Rib (VEPTR™; Synthes North America, West Chester, PA) reportedly controls spinal deformity associated with constrictive chest wall conditions. QUESTIONS/PURPOSES: We asked whether spine-to-spine constructs using VEPTR™ instrumentation in combination with standard spinal instrumentation could be deployed to salvage failed rib-to-spine constructs used originally in patients with constricted chest walls and to primarily treat progressive spinal deformity without chest wall abnormalities. PATIENTS AND METHODS: Fifty patients were treated with VEPTR™ constructs for thoracic insufficiency syndrome at our center between 2001 and 2007. Fourteen of these 50 patients had placement of a spine-to-spine construct using a VEPTR™ implant in combination with standard spinal implants and are the subject of this retrospective review. Five had prior rib-based VEPTR™ or growing implants with an average of two failures before this surgery. Radiographic variables, preceding treatment, complications, and changes in ambulatory status, were recorded. The minimum followup was 2 years (mean, 35 months; range, 2-4 years). RESULTS: After an average of five expansions in these 14 patients, positive changes were recorded for Cobb angle, T1-S1 height, sagittal balance, and space available for the lung. Complications included two rod fractures, two superficial infections, and one deep infection with rod removal. CONCLUSIONS: VEPTR™ instrumentation as a spine-to-spine growing-rod construct demonstrated ease of implantation and expansion, with complication rates similar to other reported devices. This study suggests growing constructs using VEPTR™ can be used with relatively few complications and extends the potential uses of this instrumentation system.

Scapular osteochondromas treated with surgical excision.

A retrospective review was performed of all osteochondroma excisions at our institution from 1994 to 2007. Postoperative functional assessment was completed with use of the Disabilities of the Arm, Shoulder and Hand (DASH) survey and a self-report questionnaire. Eight osteochondromas were excised at a mean patient age of 21.63 years. Presenting reports included pain, mass, pseudowinging, and snapping of the scapula. Physical examination identified pseudowinging, palpable mass, and pain with shoulder motion. The lesions arose from the ventral surface of the scapula in 5 patients, the dorsal surface in 2, and the inferior acromion in 1. The resected specimen averaged 10.8cm(3). A reactive bursa was found and resected in 4 patients. At mean of 4.17 years postresection, no signs of recurrence were found in 7 patients (88%). The single patient with a recurrence had undergone 2 additional surgical procedures. Six patients (75%) reported no/mild pain with routine and strenuous activities. One patient reported moderate and 1 patient reported moderate/severe pain with routine and strenuous activities. Four patients reported post-resection function as excellent, 2 as good, 1 as average/good, and 1 as average/poor. Six patients (75%) reported feeling very satisfied with the results, 1 reported feeling satisfied, and 1 reported feeling unsatisfied. The average DASH score was 11.7 (range, 0.00-46.67). No winging or pseudowinging was identified in those available for examination, and no difference was identified in range of motion comparing the operative to the nonoperative upper extremity. Near normal functional outcomes can be expected following excision of scapular osteochondromas.

The effects of binge alcohol exposure on bone resorption and biomechanical and structural properties are offset by concurrent bisphosphonate treatment.

BACKGROUND: Chronic alcohol consumption reduces bone mass and strength, increasing fracture risk for alcohol abusers. Mechanisms underlying this vulnerability involve modulation of bone remodeling. Direct effects of alcohol on bone formation have been documented; those on bone resorption are less well studied. Skeletal effects of exposure to high blood alcohol concentrations (BAC's) attained during binge drinking have not been studied. We examined the effects of repeated binge-like alcohol treatment on bone resorption, bone mineral density and vertebral compressive strength in adult male rats treated with the aminobisphosphonate, risedronate. METHODS: A binge alcohol exposure model was developed using intraperitoneal (IP) injection to administer a 20% (vol/vol) alcohol/saline solution (3 g/kg, 1X/day) on four consecutive days for 1, 2 or 3 weeks in 400 g rats, with and without weekly risedronate treatment (0.5 mg/kg, 1X/week). Total serum deoxypyridinoline (Dpd) a crosslink of bone type collagen released during resorption was measured by ELISA. Bone mineral density (BMD) was measured using peripheral quantitative computed tomography (pQCT). Vertebral compressive strength was determined using an Instron materials testing machine. Trabecular integrity was analyzed by computer-aided trabecular analysis system (TAS). RESULTS: Peak BAC's averaged 308.5 +/- 12 mg/dL; average BAC was 258.6 +/- 28.7 mg/dL at time of euthanasia. No significant effects of treatment were observed after 1 or 2 weeks of binge alcohol exposure. At 3 weeks of alcohol treatment serum Dpd was significantly increased (205%, p < 0.05) over controls. Bone mineral density (BMD) in cancellous bone of distal femur and lumbar spine were significantly decreased (34% and 21% respectively, p < 0.01) after 3 weeks of binge treatment. Vertebral (L4) compressive strength (maximum load sustained before failure) also decreased (27%, p < 0.05) after 3 binge alcohol cycles. Risedronate maintained the Dpd level (p < 0.01), BMD (p < 0.001) and vertebral structural biomechanical properties (p < 0.01) of binge-treated rats at control levels (E vs ER). Indices of trabecular architectural integrity [Trabecular bone volume/tissue volume (BV/TV), bone area (BAR) and trabecular separation (Tb.Sp)] analyzed at week 3 showed (BV/TV) and (BAR) were significantly reduced in alcohol-binged rats (p < 0.01), while (Tb.Sp) was significantly increased (p < 0.01). Risedronate also maintained the trabecular architectural indices of binge-treated rats at control levels (E versus ER, p < 0.01). CONCLUSIONS: In adult male rats, BAC's reflective of those attained during alcoholic binge drinking may affect the skeleton in part by stimulating bone resorption, an effect mitigated by risedronate.

Spine bone mineral density and vertebral body height are altered by alcohol consumption in growing male and female rats.

Alcohol, consumed for extended periods by growing male and female rats, impairs osteogenesis and reduces bone size and mass. The skeletal sites of experimental animals commonly chosen for an evaluation of bone mechanical characteristics and architectural properties, bone matrix gene expression, tissue concentrations of growth factors, and bone mineral density (BMD) have been the tibiae and femora. Far less attention has been focused on the spine and the effects of alcohol on vertebral BMD and vertebral body height. Fifteen male and 15 female Sprague-Dawley rats (aged 30 days) were divided into three groups: an alcohol-fed group, matched to a pair-fed non-alcohol isocaloric-fed control group with animals of the same sex, and an ad libitum-fed control group. Alcohol-fed animals received a Lieber-DeCarli liquid diet containing 36% of caloric intake as alcohol; isocaloric pair-fed rats received the same diet without alcohol. After 45 days of feeding, the lumbar spine was removed. The fourth lumbar vertebra from each spine was dissected, and the vertebral body height was measured. Lumbar vertebral body height was significantly reduced by alcohol consumption in both male and female rats compared with findings for either control group. Cancellous and cortical BMD of the vertebral body was determined by peripheral quantitative computed tomography (pQCT). Male and female rats (aged 75 days) in the ad libitum-fed group had similar vertebral body cortical and cancellous BMD, with cortical BMD being greater than cancellous BMD. Lumbar vertebral body cancellous and cortical BMD declined for both male and female rats in response to alcohol consumption for 45 days compared with findings for either control group. More BMD loss occurred from cancellous than from cortical bone in both sexes after chronic alcohol consumption. Chronic alcohol consumption by growing rats results in vertebral growth reduction and vertebral osteopenia.