Patent Application
20220387083
The field of the invention generally relates to medical devices for heating disorders of the skeletal astern.
Scoliosis is a general term for the sideways (lateral) curving of the spine, usually in the thoracic or thoracolumbar region. Scoliosis is commonly broken up into different treatment groups, Adolescent Idiopathic Scoliosis, Early Onset Scoliosis and Adult Scoliosis.
Adolescent Idiopathic Scoliosis (AIS) typically affects children between ages 10 and 16, and becomes most severe during growth spurts that occur as the body is developing. One to two percent of children between ages 10 and 16 have some amount of Scoliosis. Of every 1060 children, two to five develop curves that are serious enough to require treatment. The degree of scoliosis is typically described by the Cobb angle, which is determined, usually from x-ray images, by taking the most tilted vertebrae above and below the apex of the curved portion and measuring the angle between intersecting lines drawn perpendicular to the top of the top vertebrae and the bottom of the bottom. The term idiopathic refers to the fact that the exact cause of this curvature is unknown. Some have speculated that scoliosis occurs when, during rapid growth phases, the ligamentum flavum of the spine is too tight and hinders symmetric growth of the spine. For example, as the anterior portion of the spine elongates faster than the posterior portion, the thoracic spine begins to straighten, until it curves laterally, often with an accompanying rotation. In more severe cases, this rotation actually create a noticeable deformity, wherein one shoulder is lower than the other. Currently, many school districts perform external visual assessment of spines, for example in all fifth grade students. For those students in whom an “S” shape or “C” shape is identified instead of an “T” shape, a recommendation is given to have the spine examined by a physician, and commonly followed-up with periodic spinal x-rays.
Typically, patients with a Cobb angle of 20.RTM. or less are not treated, but are continually followed up, often with subsequent x-rays. Patients with a Cobb angle of 40.degree. or greater are usually recommended for fusion surgery. It should be noted that many patients do not receive this spinal assessment, for numerous reasons. Many school districts do not perform this assessment, and many children do not regularly visit a physician, so often, the curve progresses rapidly and severely. There is a large population of grown adults with untreated scoliosis; in extreme cases with a Cobb angle as high as or greater than 90.degree. Many of these adults, though, do not have pain associated with this deformity, and live relatively normal lives, though oftentimes with restricted mobility and motion. In AIS, the ratio of females to males for curves under 10.degree. is about one to one, however, at angles above 30.degree., females outnumber males by as much as eight to one. Fusion surgery can be performed on the AIS patients or on adult scoliosis patients. In a typical posterior fusion surgery, an incision is made down the length of the back and Titanium or stainless steel straightening rods are placed along the curved portion. These rods are typically secured to the vertebral bodies, for example with hooks or bone screws, or more specifically pedicle screws, in a manner that allows the spine to be straightened. Usually, at the section desired for fusion, the intervertebral disks are removed and bone graft material is placed to create the fusion. If this is autologous material, the bone is harvested from a hip via a separate incision.
Alternatively, the fusion surgery may be performed anteriorly. A lateral and anterior incision is made for access. Usually, one of the lungs is deflated in order to allow access to the spine from this anterior approach. In a less-invasive version of the anterior procedure, instead of the single long incision, approximately five incisions, each about three to four cm long are made in several of the intercostal spaces (between the ribs) on side of the patient. In one version of this minimally invasive surgery, tethers and bone screws are placed and are secured to the vertebra on the anterior convex portion of the curve. Currently, clinical trials are being performed which use staples in place of the tether/screw combination. One advantage of this surgery in comparison with the posterior approach is that the scars from the incisions are not as dramatic, though they are still located in a visible area, when a bathing suit, for example, is worn. The staples have had some difficulty in the clinical trials. The staples tend to pull out of the bone when a critical stress level is reached.
In some cases, after surgery, the patient will wear a protective brace for a few months as the fusing process occurs. Once the patient reaches spinal maturity, it is difficult to remove the rods and associated hardware in a subsequent surgery, because the fusion of the vertebra usually incorporates the rods themselves. Standard practice is to leave this implant in for life. With either of these two surgical methods, after fusion, the patient's Spine is how straight, but depending on how many vertebra were fused, there are often limitations in the degree of flexibility, both in bending and twisting. As these fused patients mature, the fused section can impart large stresses on the adjacent non-fused vertebra, and often, other problems including pain can occur in these areas, sometimes necessitating further surgery. This tends to be in the lumbar portion of the spine that is prone to problems in aging patients. Many physicians are now interested in fusionless surgery for scoliosis, which may be able to eliminate some of the drawbacks of fusion.
One group of patients in which the spine is especially dynamic is the subset known as Early Onset Scoliosis (EOS), which typically occurs in children before the age of five, and more often in boys than in girls. This is a more rare condition, occurring in only about one or two out of 10,000 children, but can be severe, sometimes affecting the normal development of organs. Because of the fact that the spines of these children will still grow a large amount after treatment, non-fusion distraction devices known as growing rods and a device known as the VEPTR—Vertical Expandable Prosthetic Titanium Rib (“Titanium Rib”) have been developed. These devices are typically adjusted approximately every six months, to match the child's growth, until the child is at least eight years old, sometimes until they are 15 years old. Each adjustment requires a surgical incision to access the adjustable portion of the device. Because the patients may receive the device at an age as early as six months old, this treatment requires a large number of surgeries. Because of the multiple surgeries, these patients have a rather high preponderance of infection.
Returning to the AIS patients, the treatment methodology for those with a Cobb angle between 20.degree. and 40.degree. is quite controversial. Many physicians prescribe a brace (for example, the Boston Brace), that the patient must wear on their body and under their clothes 18 to 23 hours a day until they become skeletally mature, for example to age 16. Because these patients are all passing through their socially demanding adolescent years, it is quite a serious prospect to be forced with the choice of either wearing a somewhat bulky brace that covers most of the upper body, having fusion surgery that may leave large scars and also limit motion, or doing nothing and running the risk of becoming disfigured and possibly disabled. It is commonly known that many patients have at times hidden their braces, for example, in a bush outside of school, in order to escape any related embarrassment. The patient compliance with brace wearing has been so problematic that there have been special braces constructed which sense the body of the patient, and keep track of the amount of time per day that the brace is worn. Patients have even been known to place objects into unworn braces of this type in order to fool the sensor. Coupled with the inconsistent patient compliance with brace usage, is a feeling by many physicians that braces, even if used properly, are not at all effective at curing scoliosis. These physicians may agree that bracing can possibly slow down or even temporarily stop curve (Cobb angle) progression, but they have noted that as soon as the treatment period ends and the brace is no longer worn, often the scoliosis rapidly progresses, to a Cobb angle even more severe than it was at the beginning of treatment. Some say the reason for the supposed ineffectiveness of the brace is that it works only on a portion of the torso, and not on the entire spine. Currently a prospective, randomized 500 patient clinical trial known as BrAIST (Bracing in Adolescent Idiopathic Scoliosis Trial) is enrolling patients, 50% of whom will be treated with the brace and 50% of who will simply be watched. The Cobb angle data will be measured continually up until skeletal maturity, or until a Cobb angle of 50.degree. is reached, at which time the patient will likely undergo surgery. Many physicians feel that the BrAIST trial will show that braces am completely ineffective. If this is the case, the quandary about what to do with AIS patients who have a Cobb angle of between 20.degree. and 40.degree. will only become more pronounced. It should be noted that the “20.degree. to 40.degree.” patient population is as much as ten times larger than the “40.degree. and greater” patient population.
Distraction osteogenesis, also known as distraction callotasis and osteodistraction has been used successfully to lengthen long bones of the body. Typically, the bone, if not already fractured, is purposely fractured by means of a corticotomy, and the two segments of bone are gradually distracted apart, which allows new bone to form in the gap. If the distraction rate is too high, there is a risk of nonunion, if the rate is too low, there is a risk that the two segments will completely fuse to each other before the distinction period is complete. When the desired length of the bone is achieved using this process, the hone is allowed to consolidate. Distraction osteogenesis applications are mainly focused on the growth of the femur or tibia, but may also include the humerus, the jaw bone (micrognathia), or other bones. The reasons for lengthening or growing bones are multifold, the applications including, but not limited to: post osteosarcoma bone cancer, cosmetic lengthening (both legs—femur and/or tibia) in short stature or dwarfism/achondroplasia; lengthening of one limb to match the other (congenital, post-trauma, post-skeletal disorder, prosthetic knee joint), nonunions.
Distraction osteogenesis using external fixators has been done for many years, but the external fixator can be unwieldy for the patient. It can also be painful, and the patient is subject to the risk of pin track infection, joint stiffness, loss of appetite, depression, cartilage damage and other side effects. Having the external fixator in place also delays the beginning of rehabilitation.
In response to the shortcomings of external fixator distraction, intramedullary distraction nails have been surgically implanted which are contained entirely within the bone. Some are automatically lengthened via repeated rotation of the patient's limb. This can sometimes be painful to the patient, and can often proceed in an uncontrolled fashion. This therefore makes it difficult to follow the strict daily or weekly lengthening regime that avoids nonunion (if too fast) or early consolidation (if too slow). Lower limb distraction rates are on the order of one mm per day. Other intramedullary nails have been developed which have an implanted motor and are remotely controlled by an antenna. These devices are therefore designed to be lengthened in a controlled manner, but due to their complexity, may not be manufacturable as an affordable product. Others have proposed intramedullary distractors containing and implanted magnet, which allows the distraction to be driven electromagnetically by an external stator. Because of the complexity and size of the external stator, this technology has not been reduced to a simple and cost-effective device that can be taken home, to allow patients to do daily lengthenings.
In one embodiment, an external adjustment device includes at least one permanent magnet configured for rotation about an axis. The external adjustment device further includes a first handle extending linearly at a first end of the device and a second handle disposed at a second end of the device, the second handle extending in a direction that is angled relative to the first handle. The external adjustment device includes a motor mounted inside the first handle and a first button located in the proximity to one of the first handle or the second handle, the first button configured to be operated by the thumb of a hand that grips the one of the first handle or second handle. The first button is configured to actuate the motor causing the at least one permanent magnet to rotate about the axis in a first direction.
In another embodiment, an external adjustment device includes at least one permanent magnet configured for rotation about an axis and a motor configured for rotating the at least one permanent magnet about the axis. The external adjustment device includes a first handle extending linearly at a first end of the device and a second handle disposed at a second end of the device, the second handle extending in a direction that is substantially off axis with respect to the first handle, wherein one of the first and second handle comprises a looped shape. A first drive button is located in the proximity to one of the first handle or the second handle, the first drive button configured to be operated by the thumb of a hand that grips the one of the first handle or second handle. The first drive button is configured to actuate the motor causing the at least one permanent magnet to rotate about the axis in a first direction.
The first handle 702 contains the motor 705 that drives a first external magnet 706 and a second external magnet 708 as best seen in
Distraction turns the magnets 706, 708 one direction and retraction turns the magnets 706, 708 in the opposite direction. Magnets 706, 708 have stripes 809 that can be seen in window 811. This allows easy identification of whether the magnets 706, 708 are stationary or, turning, and in which direction they are turning. This allows quick trouble shooting by the operator of the device. The operator can determine the point on the patient where the magnet of the distraction device 1000 is implanted, and can then put the external adjustment device 700 in correct location with respect to the distraction device 1000, by marking the corresponding portion of the skin of the patient, and then viewing this spot through the alignment window 716 of the external adjustment device 700.
A control panel 812 includes several buttons 814, 816, 818, 820 and a display 715. The buttons 814, 816, 818, 820 are soft keys, and able to be programmed for an array of different functions. In one configuration, the buttons 814, 816, 818, 820 have corresponding legends which appear in the display. To set the length of distraction to be performed on the distraction device 1000, the target distraction length 830 is adjusted using an increase button 814 and a decrease button 816. The legend with a green plus sign graphic 822 corresponds to the increase button 814 and the legend with a red negative sign graphic 824 corresponds to the decrease button 816. It should be understood that mention herein to a specific color used for a particular feature should be viewed as illustrative. Other colors besides those specifically recited herein may be used in connection with the inventive concepts described herein. Each time the increase button 814 is depressed, it causes the target distraction length 830 to increase 0.1 mm. Each time the decrease button 816 is depressed it causes the target distraction length 830 to decrease 0.1 mm. Of course, other decrements besides 0.1 mm could also be used. When the desired target distraction length 830 is displayed, and the external adjustment device 700 is correctly placed on the patient, the operator then holds down the distraction button 722 and the External Distraction Device 700 operates, turning the magnets 706, 708, until the target distraction length 830 is achieved. Following this, the external adjustment device 700 stops. During the distraction process, the actual distraction length 832 is displayed, starting at 0.0 mm and increasing until the target distraction length 830 is achieved. As the actual distraction length 832 increases, a distraction progress graphic 834 is displayed. For example a light colored box 833 that fills with a dark color from the left to the right. In
The two handles 702, 704 can be held in several ways. For example the first handle 702 can be held with palm facing up while trying to find the location on the patient of the implanted magnet of the distraction device 1000. The fingers are wrapped around the handle 702 and the fingertips or mid-points of the four fingers press up slightly on the handle 702, balancing it somewhat. This allows a very sensitive feel that allows the magnetic field between the magnet in the distraction device 1000 and the magnets 706, 708 of the external adjustment device 700 to be more obvious. During the distraction of the patient, the first handle 702 may be held with the palm facing down, allowing the operator to push the device down firmly onto the patient, to minimize the distance between the magnets 706, 708 of the external adjustment device and the magnet 1010 of the distraction device 1000, thus maximizing the torque coupling. This is especially appropriate if the patient is large or somewhat obese. The second handle 704 may be held with the palm up or the palm down during the magnet sensing operation and the distraction operation, depending on the preference of the operator.
Independently, Hall effect sensors 924, 926, 928, 930, 932, 934, 936, 938 may be used as non-optical encoders to track rotation of one or both of the external magnets 706, 708. While eight (8) such Hall effect sensors are illustrated in
If independent stepper motors are used, the resynchronization process may simply be one of reprogramming, but if the two external magnets 706, 708 are coupled together, by gearing or belt for example, then a mechanical rework may be required. An alternative to the Hall effect sensor configuration of
Returning to
In still another embodiment, additional information may be processed by processor 915 and may be displayed on display 715. For example, distractions using the external adjustment device 700 may be performed in a doctor's office by medical personnel, or by patients or members of patient's family in the home. In either case, it may be desirable to store information from each distraction session that can be accessed later. For example, the exact date and time of each distraction, and the amount of distraction attempted and the amount of distraction obtained. This information may be stored in the processor 915 or in one or more memory modules (not shown) associated with the processor 915. In addition, the physician may be able to input distraction length limits, for example the maximum amount that can be distracted at each session, the maximum amount per day, the maximum amount per week, etc. The physician may input these limits by using a secure entry using the keys or buttons of the device, that the patient will not be able to access.
Returning to
For example, the motor 705 would be commanded to rotate the magnets 706, 708 in a first direction when distracting an antegrade placed distraction device 1000, and in a second, opposite direction when distracting a retrograde placed distraction device 1000. The physician may, for example, be prompted by the display 715 to input using the control panel 812 whether the distraction device 1000 was placed antegrade or retrograde. The patient may then continue to use the same external adjustment device 700 to assure that the motor 705 turns the magnets 706, 708 in the proper directions for both distraction and retraction. Alternatively, the distraction device may incorporate an RFID chip 1022 which can be read and written to by an antenna 1024 on the external adjustment device 700. The position of the distraction device 1000 in the patient (antegrade or retrograde) is written to the RFID chip 1022, and can thus be read by the antenna 1024 of any external adjustment device 700, allowing the patient to get correct distractions or retractions, regardless of which external adjustment device 700 is used.
While embodiments have been shown and described, various modifications may be made without departing from the scope of the inventive concepts disclosed herein. The invention(s), therefore, should not be limited, except to the following claims, and their equivalents.
The present application is a continuation of U.S. patent application Ser. No. 16/854,499, filed Apr. 21, 2020, which is a continuation of U.S. patent application Ser. No. 16/046,916 filed Jul. 26, 2018 (now U.S. Pat. No. 10,660,675 issued May 26, 2020), which is a continuation of U.S. patent application Ser. No. 14/995,503 filed Jan. 14, 2016, which is a continuation of U.S. patent application Ser. No. 13/172,598 filed Jun. 29, 2011 (now U.S. Pat. No. 9,248,043 issued Feb. 2, 2016), which claims priority to US Provisional Application No. 61/360,353 filed Jun. 30, 2010.
| Number | Date | Country | |
|---|---|---|---|
| 61360353 | Jun 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16854499 | Apr 2020 | US |
| Child | 17819785 | US | |
| Parent | 16046916 | Jul 2018 | US |
| Child | 16854499 | US | |
| Parent | 14995503 | Jan 2016 | US |
| Child | 16046916 | US | |
| Parent | 13172598 | Jun 2011 | US |
| Child | 14995503 | US |
