SLOB

SLOB – really?

A quasi sincere apology for the name: 'SLOB' was not the intended name, but none of the five other names that were being tried or that others substituted including Summit Shelf survived. SLOB isn't really a shelf anyway. It is, evidently, just too easy to remember and it gets the radiologist's attention when written on the x-ray prescriptions - better than any of the substitutes. “ S upero- L ateral O utcropping B one-graft ” is what we wrote on the prescriptions for the post op hip x-rays, because radiologists, alarmed at the sudden new bone and extent, were calling it a possible sarcoma and putting everybody into panic. This treatment trick SLOB uses was first used by us for other troubled orthopedic bone healing situations with high success but also with similar radiology false alarms. Not one but, two of these early cases got biopsied (one at a very well known cancer hospital) where healthy new bone that was well organized was found. How it began First, why do anything? Young children have hips that are mostly soft (growing) material similar in feel to adult ears. Sustained pressure within the socket will deform the soft walled socket from its spherical shape to a slipper. The ball migrates into the pressured collapse that it is plowing. This plastic damage is called 'plastic damage' in med-speak: dysplasia. The term, Hip dysplasia , by usage default, refers to the socket and not the ball that beats the socket (ball is the hammer – socket wall is the nail).

In the old days (not THAT long ago) troubled babies did not survive. Their really super soft hips had no problems as they are not a problem in heaven. But big healthy full term babies – especially the girls made softer by mother's hormones - were getting hip flattening from late term womb compression added to by mom's

sway back. A lot of girl babies, BIG ones from all that excellent prenatal care and food availability - had flattened hips at birth, especially the left hip pressed against mom's spine. Breech babies – both sexes – commonly have one or both hips squished. Unlike flattened ears & noses from womb compression, the hips typically went unnoticed for a while. The age at which it “PRESENTED” [or adults sobered up & noticed] was anywhere from in the nursery to YEARS later. The early ones? Blame MOM = 'congenital'. The later ones? Blame nobody = 'developmental' having just kind of evolved. What?? Don't look at me! Orthopedics developed treatments to cover the range of discovered damage & displacement of the parts. The rate at which hip structure can repair shape limits self repair; bad for most late detection cases and some of the more severe early ones. Orthopedic literature is glutted with a rainbow of 'one & only' ways to treat these hips.

Academic egos aside, treatment got better and better as massive cumulative experience made it more & more difficult to deviate from whatever interventions had the best batting averages. How do you let a socket fully reform? One way was to hold the leg positioned and rotated such that the ball of the femur was exactly centered with no pressure pushing on the flat socket side and held

that way [with a body cast including leg(s)] for – oh – mmm – three YEARS!

What? Is that a problem? You bet it was. Many pediatric doctors hid the hip findings to spare children this [to them] assault on childhood. Untreated looked this way==> So, here we are – with Congenital dysplasia of the hip – or Developmental dysplasia of the hip CDH / DDH... YEARS in body casts?? To everything, turn turn, there is a season, turn turn …

One could cut the bone, and leave the upper part pointing as it was in the cast, but then move the rest of the leg to look like standing posture. Plate with screws, allows no cast, and go home. Everything good includes home. Right? The truth is that, so often, you can't go back home.

Why? What YOU called home isn't there anymore. There are rare exceptions, but, generally, everything changes. Old literature? Literature that you as a resident in orthopedics and were at home with – vast literature of CDH hip surgery – freezes mind time but not the universe in which it exists. You feel the need to do whatever [the then] science articles proved was right to do ( but which ignore ongoing changes of context – that home of CDH/DDH was indeed changing). That is where we are. Things changed. The whole world of this topic changed. But the sacred quoted literature did not. That dated old familiarity persists. People are not saying CDH or DDH... just vaguely ... children with hip dysplasia. DH An Austrian found a great & noninvasive way (ultrasound) to screen hips of newborns. Seen early, a pair of cute suspenders & stirrups fixes the newborn problem in 8 weeks!

Hip dysplasia goes AWAY!!! Yesssssss!!!!

Uh... No. You see, remember those babies that were slated for heaven? Yeah, them. They are now surviving with all the new things we have learned to do. Heaven can and did wait. Late term womb pressure isn't something these tiny kids get to experience, so their hips are as preemie as the baby, but normal . But their nervous systems? That is another story, a different story. Neurological injury often takes time to manifest as not all the circuits have gotten to where they are going yet. Damage to supportive brain cells isn't seen until that lack of supportive function chips away at the neurons that are missing that support. Again a similar gradual PRESENTATION of hip dysplasia. But it is not the same damage. This new cause (muscular pressure) which worsens with time. And the soft socket is pressed flat on the opposite side of the socket as in CDH.

Did people notice that the baby population with hip dysplasia is not the same as it was? A few did. But not the majority who are still doing VRO for this which turns the ball further into the flattened problem area rather than away (as in CDH/DDH). PDH is NOT CDH nor DDH. It is the mirror opposite. Try to look up 'PDH'. Good luck. Baby muscles that were soft with having minimal action gradually start getting waves of excessive neurological outflow for a list of reasons. Seizures, over reactive circuits amplify signals. Signal paths get fuzzy and a stream of nerve impulses intended for hither … goes hither, thither & yon, amplified as it spreads & echoes.

Abnormal posture follows, the worst being crossed legs, which directs the femur hammer directly at the soft socket edge – which in this kind of hip problem is on the exact opposite side of he socket where the CDH/DDH was pressed flatter. OK. So, in CDH & DDH the cause ( direct pressure in the womb) is gone at birth. Recenter the hip by resuming fetal posture in suspenders and the hip fixes itself. No surgery – caught early. But this is normal hips, softer than term, but normal that comes under pressure from WITHIN. And worse, the cause is NOT gone if you treat the hip. PDH (Paralytic dysplasia of the hip) is a totally different thing in every way.

So, those treatments for childhood hips – DO NOT WORK! And the academics are showing off their vast knowledge of [outdated & misapplied] hip pathology calling for the PROVEN [by CDH/DDH] science. More like batting averages, really. New game.

What we KNOW: 1. High muscle tone (especially 'dystonic') WILL deform these baby hips, and older ones as well. It is that fierce. 2. Cross leg posture focuses this abnormal pressure on the weakest part of the socket, the soft edge rather than the firm center. 3. This dysplasia is not a static anatomicdeformation – it is a process. However bad it looks now, it will look even worse next week. PDH x-rays are like a photo of windshield wipers, only capturing the moment. 4. Remove the high muscle generated pressure AND [must be “and”] abnormal crossed posture --- and the hips will be fine if damage has not yet created an inherently unstable joint as [a marble put into an empty shoe box]. 5. The palsy related muscle tendon contractures are often of greater strength than the socket walls. Muscle “STRETCHING” is only an assumption when doing stretching exercises. They should be called: Hopefully stretching muscle while not instead driving the bone out of the socket.” With the leg not aBducted, passive knee extension pistons the femur and presss the socket wall out. The femur is a huge lever and the hip socket walls are soft. At what age should we intervene to not lose the hips? Well, with CDH/DDH a few days old was certainly not too soon. It is the same with PDH in order to PREVENT dysplasia !!!! 'Early detection' [x-ray] is NOT early. You need to have substantial cartilage damage before anything – even trace change in BONE - can be seen on an x-ray. There is no ultrasound available for PDH. In PDH the cause isn't going away, it is increasing. You do not need x-ray to see the cause . We can see what damages these hips [using eyeballs] and feel the tension [hands] – we don't need a test that documents only our clinical ignorance. If you see someone choking a child, do we order an x-ray to see if the windpipe is truly collapsed – and if so - then ask if the perp will stop? We know that our CP perpetrator will NOT. But the CDH/DDH treatments for late damage involve chisels & metal plates and breaking and shortening bones and so on. To PREVENT (given visual & palpable evidence of the PROCESS that causes damage) small targeted nerve injection (ethanol) and a very tiny division of the abnormal reflex trigger parts of the self amplifying [similar to microphone feedback] is simple & outpatient. PREVENTION. In children less than 1 yo, it often lasts several years. We have no cases of later hip reconstruction in those treated early before damage, or those with minimal evidence as seen by ultrasound (different kind than the CDH/DDH variety).

One big exception.

Unfortunately, seizures can quickly destroy any hip, even a completely intact mature hip. Seizure activity erases learning, damages the brain more, and can do serious damage to normal anatomy. Detection of seizure activity or heightening of known and treated seizure activity is important – especially going into puberty when it is most common to surprise everybody. SLOB is the only thing that we know of that protects hips through seizures. SLOB produces greater socket strength and hip stability than is normal with more protective surface to distribute abnormal forces. We will show this later. Just note that SLOB is not an attempt to normalize a prior damage. In PDH the gun that fired before is still loaded and still firing. We don't need a new shirt. We need armor.

If the hip socket is visibly damaged but not fully dislocated, the SPMLs cannot prevent what has already happened. Hip damage can be mechanically self promoting. We had already devised a method for some very resistant uses of bone grafting that required speedy and strong bone graft (to fill large cysts and to fuse certain high stress joints). Rather than putting in hard “cortical” bone [feels like hard wood], which often fails, we used cadaver processed soft cancellous bone which is more air than bone. We kneaded a bone morphogenic protein (BMP) gel into that crunchy soft matrix plus bone marrow. BMP tells bone stem cells to “MAKE BONE” and those cells (living in marrow) will transform quickly into bone making tissue. That is why we laced the BMP gel with bone marrow (bone stem cells) that we harvest at the time of surgery. The bone stem cells are driven wild by BMP protein. New bone rapidly forms as driven stem cells consume the surrounding matrix that we molded in place to hold the shape of what is wanted of the new bone. As new bone forms it becomes very quickly visible whereas the initial matrix is not seen on x-ray. Poof, there it is – so it seemed to radiologists who had no idea how the bone had gotten so far so fast (we put it there – just couldn't see it). The fastest area was the superior and lateral near the top of the hip on the side of the pelvis. We noted it on our x ray request forms. This material, as prepared, has a crunchy clay feel. We pack it into a space that we create - a shape where we want bone to be - and seal it closed (sutures). It is similar to stuffing tuna into a pita bread pocket.

So who needs this? Not this person (left) who had the dysplasia prevented (SPMLs with ethanol perineural selective focal injections). Below = 19 yr followup.

SPML can reverse SOME that have 'uncovering' and 'mild' displacement, but it isn't guaranteed. Better function – sure. Reversal of hip deformity, maybe. Before we had SLOB intervention we gave many a trial period with SPML alone. As shown above. Things that we are sure to make luck less likely include seizure activity without good control, dystonia especially with windswept posture, megacolon that isn't remedied, and older patients with less biologic ability to remodel bone. Megacolon? Distended bowel is common in dystonia. Common is not OK. Custer's soldiers commonly had arrows in their chests. Distended bowel sets up a neurological howl that manifests as amplified reflex lower limb dystonic posturing. It causes hip dislocation . Also, unwitting clinicians are treating REFLUX that originates with colon distention that loses propulsion directionality. High bacterial load also makes these kids look and feel sick. Hence we have “TOXIC” megacolon. Parallel loops of small bowel seen on hip screening x-rays should alert you to the need for a pediatric gastroenterologist, and not Nissen fundoplications for undiagnosed colonic stasis causing reverse peristalsis. When there is visible paralytic hip dysplasia in these children (especially those with dystonic features) then SLOB is far easier and safer than VRO or VRO plus pelvic whatever. VRO is so asymmetrical (lop sided) that it is seldom done unilaterally. Bilateral VRO is a massive metabolic hit. That metabolic cost overload manifests as wound problems, nonunion, metal breakage, and lots of stuff that would not otherwise

be suspected. If you understand burns then you understand this. The word is not out in many places. So, we see late comers.

We glossed over detail of what SLOB is. We will fix that now. Angular pressure of the femur presses the acetabular back wall backward and flatter. The hip ball displaces within this advancing pocket that it plows.

The hip was made for optimum movement using optimum control. It has no defense against sustained angular backward thrusting caused commonly by dystonic reflex patterns. “Windswept” posture (both legs leaning together toward one side) will have the adducted hip (this case = left) socket damaged more than the opposite side which is centered by the dystonia. Normal structure cannot withstand these piston adducted forces. If you see windswept, or sustained scissoring posture, then you have seen all the early detection you need in order to prevent hip damage that follows not relieving the hip from this destructive process. 'Early detection' is posture observation. A 'normal' x-ray does not = a normal hip as x-rays are blind to the cartilage damage. In the above illustration of adduction pressure damaging the shallow socket, notice the upper right inset of a hip ball-in-socket in white vs. a striking bag (boxer's speed bag) ball in socket (light blue). The latter is the goal of SLOB reinforcement. Turn a yarmulke into a football helmet.

Shenton's line: The femoral neck and the pubis form a graceful arch. You can visualize an egg shape extending the line on both sides. The neck shaft angle (~ 120 degrees) will look flat if

not seen side -on. This is commonly misidentified as 'valgus'. It isn't. In the inset the leg simply has been rotated from the best neck-shaft viewing projection. Two shallow hips with similar uncovering. But one for sure has acetabular wall deformation as Shenton's Line reveals. That can be made less but securing it = S.L.O.B.

The yellow seen inside the hip is the cartilage. The tan Y shaped tendon is the tendon of the rectus femoris. The “reflected head” of the tendon outlines the acetabulum and displaces with the acetabular deformation. The shallow part of the socket can be

undercut into the bone to allow the flattened part to be curled into the original deeper shape. We stack shaped wedges into the created space to hold its restored contour. Also the growing edge is curled so as to point the way to making growth in the direction of deepening.

This is the general plan for S.L.O.B. Muscles that promote the damaging force are lengthened or divided (based on degree), or moved to alter the kind and directionality of motion. The red is exposed marrow as the flat cup wall is curved down at the top, and forward in the back. Curved wedges are tamped into this space. A pyramid of mold-able stuff is packed along the side of the pelvis over the capsule covering the head of the femur to mid neck. This becomes bone by being consumed and converted to bone. Growth under the cover of that new bone must follow the down & out contour. Thus the native hip can and does deepen. The ridge in the bone-graft caused by the rectus femoris reflected head allows a very accurate marker for assessing original hip from augmented hip. Sometimes, portions seem to not have made bone, but ultrasound, MRI, probe, and outlining air injection as well as biopsy has taught us that this is very tough uncalcified bone. It works either way calcified or not. We call it shark bone as that is what our radiologists called it.

We need to CLARIFY something about SLOB. The name was a reaction to grab the attention of RADIOLOGISTS so as to not call what they see as 'sarcoma', even 'possibly sarcoma'. We had two cases where patients rushed to cancer hospitals for biopsy (= new bone formation). Imagine the mind job that 'sarcoma' did on those families! They were reacting to the superolateral spreading bone line which is from the iliac periosteum which is peeled up and lateralized by the packed in new bone. There is more bone graft posterior but that didn't ring anybody's alarm bells. So the bone is supero Lateral & Posterior bone gract. See the gray blob above. The psoas/iliacus is lengthened (intrapelvic) and the rectus femoris recessed into the rest of the quadriceps (direct head divided but reflected head remains creating a visible notch in the new bone which allows following real old socket repair from the new. SPMLs handle the rest of muscular tension balancing.

Stacked 'elevators' (narrow underneath wide) allow very controlled contouring of the acetabular wall being reshaped around the femoral head. Contoured wedges are radially tamped to hold the shape.

Look at the date, 2001. Back then we had no Cafe'Door method to bail out such way way too late cases. So we pushed SLOB much further than we do today. That required some lengthening and bracing gymnastics to place and hold hip position until bone was solid enough to take over. SLOB, today is far better than back then because these too far gone cases are now Cafe'Door (which has SPML and SLOB included within the tall list of things that make up the Cafe'Door surgery. It takes a page just to list the parts, but it works... reliably.

By 4 weeks we have lots of bone. We need to toughen this new bone. That is done by weight bearing. Weight bearing begins in ~ 4 weeks if the x-ray looks good.

Bilateral SLOB Upper left inset has both hips uncovered and both Shenton's lines are badly offset. Hips are subluxed (subluxation = ball off center in deformed acetabulum, on their way toward dislocation). SDR & SLOB Selective Dorsal Rhizotomy cuts sensory nerve rootlets to reduce recycling signals. The reduction in spasticity is quite impressive. Yet, the imbalance persists. That imbalance is what damages the hip. If such damage is already present, SDR will not only not treat it, the loss of hip structure accelerates as lower tension allows the ball to ride more lateral with greater ability to do damage and with less medial compression to keep the ball in deep. This is common to many conditions. Low tone asymmetry dislocates more and faster than high tone. If Shenton's Lines are broken, it is wise to not do SDR until that instability has been eliminated and muscular imbalance made better.

Restricted Range?

Abduction is not blocked.

Recap: The hip socket is similar to a yarmulke tilted closer to one ear. It is smaller than the head and so does not fully contain the femoral head. The “uncovering” that people love to measure is that of the lateral side. That can result simply from adduction (leg crossing) alone. So uncovering % alone is unclear.

If it is from a too shallow cup then OK. Displacement of the ball center from the cup center is impossible unless the acetabular walls are breached, pushed out allowing the ball sideways sliding. The plan is to first reduce the asymmetrical forces. SPML is done as is ethanol nerve things, but SLOB adds recession of the rectus femoris from the pelvis and letting it be like the rest of the quadriceps of which it is part. The iliopsoas is also lengthened (intra pelvic). The flattened region of socket is reshaped and bone wedges hold that. A big blob of bone marrow /matrix/BMP is molded into place turning the yarmulke hip socket into a football helmet.

The left hip SLOB (dated 7/02 = 2002) seen just prior was in a child with a reasonably good opposite hip. It had never varied on yearly x-rays.

Then a serious seizure came from out of the blue requiring emergency room intervention.

At our request this x-ray was taken. The SLOB hip survived.

The other did not.

This is not isolated. Even more mature patients with zero indication of hip dysplasia get hip damage in the wake of seizures.

This is our preferred “HIP POSITIONING BRACE”. It is cheap & light weight. The lower metal band is well above the iliac crest (away from the surgical incision). Plastic pelvic braces are not only not good at holding position (they slant every which way the dystonia likes to go), they also rub the incision and are hot. Rather than steel (heavy) adjustable hinges, simple metal bending of duraluminum gets the angulation job done in a third the cost with no added weight. Adjustable ($teel) hip joints are very heavy.

It is an old polio brace kit with a second higher ring into the armpit area to control the lower ring. The upper ring can be padded aluminum as here or all leather. This breathes much better than plastic and is much cheaper. We will review much of this in a different context when discussing Cafe'Door reconstruction for paralytic dysplasia with dislocation of the hip.

Go take a break. This was a lot to absorb.